Find the circumference of a circle with radius of 18 in. Leave your answer in terms of π

Answers

Answer 1
C=2πr
C=2(18)π
C=36π in.
Answer 2
The formula for circumference is 2*pi*r

C = 2*pi*18
C = 36pi

Related Questions

What is the polygon being rotated to create the brown quilt block pattern?

Answers

It would be a parallelogram since if you look closely the individual shapes are indeed parallelograms.

Answer with explanation:

The pre image which is in blue color is parallelogram.

There are four blue parallelograms here,congruent to each other,each one of them when rotated by certain angle ,gives parallelogram in brown color.

When we rotate a polygon,after rotation neither the shape nor the size of polygon changes.The two shapes are congruent to each other.

The Polygon being rotated to create the brown quilt block pattern is

Option C: Parallelogram

If 35% of a natural area is to be developed, leaving 500 acres untouched, how many acres are to be developed?

Answers

Answer:

Area to be developed = 269.23 acres

Step-by-step explanation:

Let there is A acres natural area to be developed.

If 35% of A acres is developed then untouched area will be (100 - 35 = 65%)

Now it has been given in the question that 65% of A (untouched area) = 500 acres

[tex]A.\frac{65}{100}=500[/tex]

[tex]A=\frac{500}{0.65}=769.23[/tex]

So area of the natural field = 769.23 acres

Now 35% of the natural area which is to be developed = A×35%

[tex]=769.23.\frac{35}{100}=(769.23)(.35)=269.23[/tex]

Area of the natural area to be developed is 269.23 acres

The number of acres that are to be developed is 269 acres.

Number of acres

Using this formula

Number of acres=(Number of acres untouched/(100%-Percentage of natural area)×Percentage of natural area

Let plug in the formula

Number of acres=500 acres/(100%-35%)×35%

Number of acres=(500 acres/65%)×35%

Number of acres=769.23×35%

Number of acres=269 acres

Inconclusion the number of acres that are to be developed is 269 acres.

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what is the degree of 12x^4-8x+4x^2-3

Answers

dat is 4th degree because x is raised to the 4th power and that is the highest power of the placholder

4th degree

Answer:

The degree of [tex]12x^4-8x+4x^2-3[/tex] is 4.

Step-by-step explanation:

The given polynomial is [tex]12x^4-8x+4x^2-3[/tex]

This polynomial is of one variable which is x. Hence, the degree of the polynomial is the highest exponent.

For the given polynomial, the highest exponent is 4.

Therefore, the degree of [tex]12x^4-8x+4x^2-3[/tex] is 4.

Find all solutions to the equation in the interval [0, 2π). cos 2x - cos x = 0

Answers

this is the concept of algebra, to solve the expression we proceed as follows;
cos 2x-cosx=0
cos 2x=cosx
but:
cos 2x+1=2(cos^2x)
thereore;
from:
cos 2x=cos x
adding 1 on both sides we get:
cos 2x+1=cos x+1
2(cos^2x)=cosx+1
suppose;
cos x=a
thus;
2a^2=a+1
a^2-1/2a-1/2=0
solving the above quadratic we get:
a=-0.5 and a=1
when a=-0.5
cosx=-0.5
x=120=2/3π
when x=1
cos x=1
x=0
the answer is:
x=0 or x=2/3π

Answer:

The other answer is correct here except it is missing the answer 4pi/3

other wise its correct. The answers are 0, 2pi/3, and 4pi/3

Step-by-step explanation:

see previous answer

Help Please!!!!!!

f(x)=5x^2+9x−4

g(x)=−8x^2−3x−4

Find (f+g)(x)

My Options Are...:
a. 3x^2+6x−8
b. −3x^3+6x^2−8x
c. −3x^4+6x^2−8
d. −3x^2+6x−8

Answers

f+g(x)=5x^2+9x-4-8x^2-3x-4
Combine like terms
f+g(x)=-3x^2+6x-8
Final answer: D

The perimeter of a rectangle is 276 centimeters. It's length is five times its width. What are the dimensions?

Answers

think of this this way
length = 5x
width = x
perimeter = 276
Its always easier to write down your givens in an equation

5x + x + x + 5x = 276
12x = 276
x = 23

The width is 23 cm
The length is 115 cm

A baseball team has won 13 out of 18 games they played this session. How many additional games must the team win in a row to raise its winning percentage to 80%?
A) 7
B) 14
C) 5
D) 24

Answers

The answer to that question is A, 7.
Yes the answer is 7.

Determine the distance between a(-1, 2,3) and b(4,-5, 6) to the nearest tenth

Answers

hello :
 the distance between A(-1, 2,3) and B(4,-5, 6)
AB= √((4-(-1)²+(-5-2)² + (6 - 3 ) ²) =√(25 +49 +9) =  √83 ≅ 9.11

what level of measurement is qualitative? Nominal? Ordinal? Interval? Or ration?

Answers

interval.............................


The level of measurement which is qualitative is nominal.
It is the only level of measurement which is only qualitative, whereas ordinal can be either qualitative or quantitative (depending on data), and interval and ratio can only be quantitative.
The term qualitative refers to the fact that non-numerical entries are used, meaning there are no numbers, and the word nominal refers to the Latin word for nouns, or words, which is why that is the correct answer. The rest of the options use numbers, but nominal doesn't.

PLEASE HELP ASAP 20 POINTS PLUS BRAINIEST!

Find the greatest possible error for each measurement.

3 ft

a.
1 ft
b.
1/2 ft
c.
1/4 c
d.
1/6 c

Answers

the greatest possible error when measuring in feet is 1/2 foot

 answer is B


Find the missing factor x(y+6)-5(y+6)( ) (y+6)

Answers

We are given the equation:

x (y + 6) – 5 (y + 6)                           ---> 1

We are to look for the missing factor in the equation: (_) (y + 6) from the given values.

Knowing the rules of the polynomial multiplicity, we can have an idea that the given equation can also be written in the form of:

(x – 5) (y + 6)                                      ---> 2

wherein the whole factor (y + 6) was simply distributed to the values in the factor (x – 5). To prove that equations 1 and 2 are equal:

x (y + 6) – 5 (y + 6) = (x – 5) (y + 6)

Expanding:         

x y + 6 x - 5 y – 30 = x y + 6 x – 5 y – 30     (EQUAL!)

 

Therefore our missing factor is:

(x – 5)

what are the roots of the polynomial equation x3-7x=6x-12? Use a graphing calculator and a system of equations.

Answers

x3-7x=6x-12
x3-7x-6x+12=0
x3-13x+12=0
(x-1)(x2+x-12)=0
Calculate delta of the second bracket:
delta = 1+4*12=49
sqrt(delta)=sqrt(49)=7
x_1=(-1-7)/2=-4
x_2=(-1+7)/2=3

(x-1)(x+4)(x-3)=0

Answear:
Roots: x=1, x=-4, x=3.

The roots of the polynomial equation x³ - 7x = 6x - 12 is x = 1, 3, -4 and graph is shown in the picture.

What is polynomial?

Polynomial is the combination of variables and constants systematically with "n" number of power in ascending or descending order.

[tex]\rm a_1x+a_2x^2+a_3x^3+a_4x^4..........a_nx^n[/tex]

We have a polynomial equation:

x³ - 7x = 6x - 12

[tex]\rm x^3-7x+12=6x[/tex]

x³ - 13x + 2 = 0

(x - 1)(x -3)(x + 4) = 0

x = 1, 3, -4

Thus, the roots of the polynomial equation x³ - 7x = 6x - 12 is x = 1, 3, -4 and graph is shown in the picture.

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PLEASE HELP!!! Evaluate Show your work.

Answers

well first you have to distribute the sqrt (7x). So:
sqrt (7x)(sqrt (x) - 7sqrt (7)) =
sqrt (7x) * sqrt (x) - sqrt (7x) * 7sqrt (7)

now if you have two things multiplied by each other and they are both under the sqrt sign then we can multiply them by each other But we have to leave them under the sqrt sign. so this becomes:
sqrt (7x * x) - 7sqrt (7x *7) =
sqrt (7x^2) - 7sqrt (7^2 *x)

in the first sqrt we have x^2 And in the second we have 7^2. The sqrt of anything squared is the same number without the square. So sqrt (x^2) becomes x and sqrt(7^2) becomes 7. So now we have:
x * sqrt (7) - 7 * 7sqrt (x) =
xsqrt (7) - 49sqrt (x)

Answer:

[tex]\sqrt{7x}(\sqrt{x}-7\sqrt{7})\Rightarrow x\sqrt{7}-49\sqrt{x}[/tex]

Step-by-step explanation:

Given: [tex]\sqrt{7x}(\sqrt{x}-7\sqrt{7})[/tex]

Simplify the expression.

[tex]\Rightarrow \sqrt{7x}(\sqrt{x}-7\sqrt{7})[/tex]

Distribute  [tex]\sqrt{7x}[/tex] over parentheses

[tex]\Rightarrow \sqrt{7x}\cdot\sqrt{x}-\sqrt{7x}\cdot7\sqrt{7}[/tex]

[tex]\Rightarrow \sqrt{7x^2}-7\sqrt{7^2x}[/tex]

square term take out from square root

[tex]\Rightarrow x\sqrt{7}-7\cdot 7\sqrt{x}[/tex]

[tex]\Rightarrow x\sqrt{7}-49\sqrt{x}[/tex]

[tex]\sqrt{7x}(\sqrt{x}-7\sqrt{7})\Rightarrow x\sqrt{7}-49\sqrt{x}[/tex]

In the triangle below, determine the value of a.

Answers

tan42°=a/14

a=14tan42°

a≈12.61 (to the nearest hundredth of a unit)
You have to use tangent (ratio of sine and cosine).

Use tangent to find the opposite to the adjacent side (14) from the angle (in this case a).

a = 14*tan(42°) = 14*0,9 = 12,6 (approssimatively)

Match the pairs of values of f(x) and g(x) with the corresponding values of h(x) if h(x) = f(x) ÷ g(x).

Screenshot of the tiles below

(Please help)

Answers

1)f(x)/g(x)=(x^2-9)/(x-3)=x+3
2)f(x)/g(x)=x^2-4x+3/x-3=x+1
3)f(x)/g(x)=x^2+4x-5/x-1=x+5
4)f(x)/g(x)=x^2-16/x-4=x+4

The We have given that the pairs of values of f(x) and g(x) with the corresponding values of h(x) s given below.

(x^2-9)/(x-3)

x^2-4x+3/x-3

x^2+4x-5/x-1

x^2-16/x-4

We have to match the pairs  of values of f(x) and g(x) with the corresponding values of h(x) if h(x) = f(x) ÷ g(x).

What is the function?

A function from a set X to a set Y assigns to each element of X exactly one element of Y. The set X is called the domain of the function and the set Y is called the codomain of the function. Functions were originally the idealization of how a varying quantity depends on another quantity.

1)f(x)/g(x)=(x^2-9)/(x-3)=x+3

2)f(x)/g(x)=x^2-4x+3/x-3=x+1

3)f(x)/g(x)=x^2+4x-5/x-1=x+5

4)f(x)/g(x)=x^2-16/x-4=x+4

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If isosceles triangle ABC has a 130° angle at vertex B, which statement must be true?
m∠A = 15° and m∠C = 35°
m∠A + m∠B = 155°
m∠A + m∠C = 60°
m∠A = 20° and m∠C = 30°.

Answers

isocolese triangle has 2 angles of same length

all angles in a triangle add to 180

so
if the angles are m∠A, m∠B, m∠C, then
either m∠A=m∠B or m∠B=m∠C or m∠A=m∠C

anyway

so if we assume that vertex B is the one that has a twin then
130+130+?=180
260+?=180
?=-80
false, we can't have a negative angle measure

so 130 must be the odd one

?+?+130=180
2?+130=180
2?=50
?=25

so
m∠A=m∠C=25°

let's test the 2nd answer choice
m∠A+m∠B=25+130=155, yep

test 3rd
m∠A+m∠C=25+25=50≠60, nope
not 3rd one



so answer is 2nd statement
m∠A + m∠B = 155°

Find the prime factors of each of the following numbers. a. 25 b. 38 c. 36 d. 285 e. 650 f. 1,740

Answers

Gonna give u how to do it and then u sdo it for each one:

You have to try all prime numbers less or equal than the sqrt(number).

Example: 285, sqrt(285) =16.88194301613413

Try all below 16: 2, 3, 5, 7, 11 and 13:

285 / 3 = 95, 95 / 5 = 19 (19 is prime, end),

285 = 3*5*19, the prime factors are 3, 5 and 19

25 = 5*5
38=2*19
36 = 2^2 * 3^2, so 2 and 3.

That's why I let you do the last one

Answer:

The prime factors are:

a. 5 and 5 (5 × 5 = 25)

b. 2 and 19 (2 × 19 = 38)

c. 2, 2, 3, and 3 (2 × 2 × 3 × 3 = 36)

d. 3, 5, and 19 (3 × 5× 19 = 285)

e. 2, 5, 5, and 13 (2 × 5 × 5 × 13 = 650)

f. 2, 2, 3, 5, and 29 (2 × 2 × 3 × 5 × 29 = 1,740)

Step-by-step explanation:

straight from Penn

Which polynomial is a perfect square trinomial?

A. 36x²-18x-9
B. 4a²-28a-49
C. 25b²-40b+16
D. 4x²-6x+9

Answers

ANSWER: C
because of how the multiples of 25 are 5 and 5 and the multiples of 16 can be -4,-4...
 5*-4+5*-4=-40
(5x-4)²= ((5²)x²-40x+(-4²))=25x²-40+16
C
//Brief explanation
Using a discriminant (b^2 - 4ac), for a perfect square the discriminant = 0.
For A the discriminant is >0 (1620)
For B the discriminant is >0 (1568)
For C the discriminant = 0
For D the discriminant is < 0 (-108)

Which of the following equations describes the graph shown?

A.) y = x+2

B.) y = -x - 2

C.) y = x - 2

D.) y = -x + 2

Answers

By looking at the slant at which the line is going, you can tell if the line is negative or positive. This line is negative, so that removes two of the choices. By looking at where the line intersects the y-axis determines if its negative or positive. So the answer is D

Answer: The correct option is (D) y = -x + 2.

Step-by-step explanation:  We are to select the correct equation that describes the given graph.

We can see that the graph is a straight line passing through the points (0, 2) and (1, 1).

So, the slope of the line will be

[tex]m=\dfrac{2-1}{0-1}=-1.[/tex]

Therefore, the equation of the line with slope m = -1 and passing through the point (0, 2) is given by

[tex]y-2=m(x-0)\\\\\Rightarrow y-2=-1\times x\\\\\Rightarrow y-2=-x\\\\\Rightarrow y=-x+2.[/tex]

Hence, the equation that describes the graph is  y = -x + 2.

Thus, (D) is the correct option.

I NEEED HELPOPOP!!!!

PLEASE ASSIT ME FOR TWO MATH QUESTIONS

Answers

Hello,

The only function in B has an inverse which is also a function (one x must have only 0 or 1 image (y)) for the first picture

Answer D for the second picture.


Answer B

What is the equation of the line that is parallel to the line y = x + 4 and passes through the point (6, 5)?

Answers

y-5=1(x-6)

y-5=x-6

y=x-1 is parallel to y=x+4

The figure shows secant GC and tangent GB intersecting to form an angle. Find x and y If necessary, round to the tenths place.

Answers

Measure of arc DB = 58°. So ∠ C = 58° : 2 = 29°
Let`s look at the triangle: Δ GBC. GB is a tangent.
29° + 90° + y = 180°
y = 180° - 90° - 29° = 61°
Then ∠ B = 30° : 2 = 15°
In a triangle ΔADC :  ∠ A = 180° - ( 29° + 15° ) = 180° - 44° = 136°
x = 180° - 136° = 44°
Answer: x = 44°,  y = 61°

The value of y, calculated using the difference between the intercepted arcs, is 69.5° when rounded to the tenths place.

The figure provided depicts a circle with a secant (line GC) and a tangent (line GB) intersecting at point G, forming an angle. There are several angle measures given in the figure: angle ECA is 30°, angle ADB is 58°, and angle EAB is 161°. The angles x° and y° are what we need to find.

Here's how to find x and y:

1. To find x:

  - The angle formed by a tangent and a chord (GB and BA in this case) is equal to the angle in the alternate segment of the circle. Therefore, x is equal to the angle in the alternate segment, which is angle ADB (58°). So, x = 58°.

2. To find y:

  - The angle formed by a tangent and a secant (GB and GC in this case) from the external point G is equal to the difference between the measure of the intercepted arc (the large arc EAC) and the measure of the adjacent arc (the small arc EC). This can be calculated by the formula [tex]\( y = \frac{1}{2}(\text{large arc} - \text{small arc}) \).[/tex]

  - The large arc EAC is the full circle (360°) minus the small arc EBC (161°), so the measure of arc EAC is 360° - 161° = 199°.

  - The small arc EC is twice the angle ECA (which is an inscribed angle) because the measure of an arc is twice the measure of an inscribed angle that subtends it. So, the measure of arc EC is 2 * 30° = 60°.

  - Now we can calculate y using the formula: [tex]\( y = \frac{1}{2}(199 - 60) \).[/tex]

Let's calculate the exact values for x and y.

The value of x is equal to the angle ADB, which is 58°.

The value of y, calculated using the difference between the intercepted arcs, is 69.5° when rounded to the tenths place.

Therefore, [tex]\( x = 58 \) and \( y = 69.5 \).[/tex]

What is the equation of a line that has a slope of -5 and passes through the point (0, 2)?

Answers

The equation is [tex]y = -5x + 2[/tex]. This is because the slope form is y = mx + b, and if -5 is the slope, -5 = m. 2 is the y-intercept, and the y-intercept is b.

Write cos 53 degrees in terms of sine.

Answers

cos(x) = sin(90 - x)
cos(53) = sin(90 - 53)
cos(53) = sin(37)

The value of cos 53 degrees in terms of sine is,

⇒ sin 37 degree

What is mean by Angle?

An angle is a combination of two rays (half-lines) with a common endpoint. The latter is known as the vertex of the angle and the rays as the sides, sometimes as the legs and sometimes the arms of the angle.

We have to given that;

⇒ cos 53 degree

Hence, We can change it into sine as;

⇒ cos 53 degree

⇒ sin (90 - 53)

⇒ sin 37 degree

Thus, The value of cos 53 degrees in terms of sine is,

⇒ sin 37 degree

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A hyperbola centered at the origin has a vertex at (3, 0) and a focus of the hyperbola is located at (9, 0). What are the equations of the directrices?
x = ±

Answers

Final answer:

To find the equations of the directrices for a hyperbola centered at the origin with a vertex at (3, 0) and a focus at (9, 0), we use the formula x = ±a/e. The hyperbola's directrices are x = ± 1.

Explanation:

The student asked about the equations of the directrices for a hyperbola that is centered at the origin, with a vertex at (3, 0) and a focus at (9, 0). A hyperbola has two directrices, and each is a line that is perpendicular to the transverse axis and equidistant from the center as the foci are, but on the opposite side. The equation of a directrix can be found using the formula x = ±a/e, where 'a' is the distance from the center to the vertex and 'e' is the eccentricity, which is the ratio of the distance from the center to a focus (c) over 'a'.

In this case, the hyperbola is aligned along the x-axis. Given a vertex at (3, 0), it implies that 'a' is equal to 3. Since the focus is at (9, 0), it suggests 'c' is equal to 9. The eccentricity 'e' can be found by e = c/a, which is 9/3 = 3. Using the directrix formula x = ±a/e, the two directrices of the hyperbola would be x = ±(3/3), which simplifies to x = ± 1.

Fill in the missing term in the equation. x/x^2-4x+4-x/x^2-3x+2=?/(x-2)^2(x-1)

Answers

           x                            x
-----------------  -  --------------------
x^2 -4x + 4            x^2-3x+2

           x                            x
= ----------------  -  --------------------
    (x -2)^2            (x - 2)(x - 1)

        x (x-1)  - x(x +2)                       
= ----------------------------
          (x -2)^2 (x - 1)

      x^2 -x -x^2 - 2x                    
= --------------------------
      (x -2)^2 (x - 1)

           -3x                    
= -----------------------
      (x -2)^2 (x - 1)

answer 
missing term in the equation: -3x

Answer:

The missing term is x.

Step-by-step explanation:

Given expression is,

[tex]\frac{x}{x^2-4x+4}-\frac{x}{x^2-3x+2}------(1)[/tex]

Since, [tex]x^2-4x+4=(x)^2-2\times (2x)+(2)^2[/tex]

[tex]\implies x^2-4x+4=(x-2)^2------(2)[/tex]    ( (a-b)² = a² - 2ab + b² )

Now,   [tex]x^2-3x+2=x^2-2x-x+2[/tex]    ( By middle term splitting )

[tex]=x(x-2)-1(x-2)[/tex]

[tex]\implies x^2-3x+2=(x-1)(x-2)------(3)[/tex]

From equation (1), (2) and (3),

[tex]\frac{x}{x^2-4x+4}-\frac{x}{x^2-3x+2}=\frac{x}{(x-2)^2}-\frac{x}{(x-2)(x-1)}[/tex]

[tex]=\frac{x(x-1)-x(x-2)}{(x-2)^2(x-1)}[/tex]

[tex]=\frac{x(x-1-x+2)}{(x-2)^2(x-1)}[/tex]

[tex]=\frac{x(1)}{(x-2)^2(x-1)}[/tex]

[tex]=\frac{x}{(x-2)^2(x-1)}[/tex]

Hence, the missing term in the equation is x.

He nine ring wraiths want to fly from barad-dur to rivendell. rivendell is directly north of barad-dur. the dark tower reports that the wind is coming from the west at 68 miles per hour. in order to travel in a straight line, the ring wraiths decide to head northwest. at what speed should they fly (omit units)?

Answers

This problem is better understood with a given figure. Assuming that the flight is in a perfect northwest direction such that the angle is 45°, therefore I believe I have the correct figure to simulate the situation (see attached).

 

Now we are asked to find for the value of the hypotenuse (flight speed) given the angle and the side opposite to the angle. In this case, we use the sin function:

sin θ = opposite side / hypotenuse

sin 45 = 68 miles per hr / flight

flight = 68 miles per hr / sin 45

flight = 96.17 miles per hr

Solve 152x = 36. Round to the nearest ten-thousandth.



A. 0.6616


B. 2.6466


C. 1.7509


D. 1.9091

Answers

x = 36 / 152 = 0.2368

Since no one was getting the the answer that is on the assignment I plugged  the problem into an algebra calculator, and got A 0.6616

the square has a radius of 3 square root 2 what is the apothem?

Answers

Final answer:

The apothem of the square is equal to half the length of a side of the square, which can be calculated by doubling the radius. In this case, the apothem is 3√2.

Explanation:

The apothem of a square is a line segment drawn from the center of the square to any side of the square, perpendicular to that side. The apothem is equal to half the length of a side of the square.

Given that the square has a radius of 3√2, we can determine the length of a side of the square by doubling the radius. So, the length of a side is 2 * 3√2 = 6√2.

Therefore, the apothem of the square is half the length of a side, which is (6√2)/2 = 3√2.

What is the value of 35+20/5-4*7
11
49
245
35
Hellllpp :)

Answers

35+20/5-4*7 = 35 + (20/5) - (4*7)
= 35 + 4 - 28 = 11

The answer is 11
Follow the order of operations or PEMDAS. P for parentheses, E for exponents, M and D for multiplication and division (do these left to right and NOT all multiplication before division), then A and S are for addition and subtraction... Also do these left to right. So
35 + 20/5 - 4×7 =
35 + 4 - 28 =
39 - 28 =
11
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1. Evaluate 6.314 - 9.77.3.456-3.464-3.456-16.0842. Evaluate -5.118 - (-4.1).-9.218-1.0181.0189.2183. Find the value of x + y for x = 75.9 and y = 2.65.10.24102.478.5579.554. Find the value of -x + y for x = 75.9 and y = 2.65.-78.5578.5573.25-73.25 What is the probability that a randomly selected person will have a birthday in march? assume that this person was not born in a leap year. express your answer as a simplified fraction or a decimal rounded to four decimal places? 5/14 divided by 3/4, what's the answer Solve 2a 2 - 3a - 2 = 0{-1/2, 2}{1/2, -2}{} Find the area of the triangle What 1 medical field would use information regarding integumentary, skeletal/muscular, and digestive system knowledge? HELP NOW PLEASE!1. STORIES OF USEFUL INVENTIONS, excerptBy S. E. Forman1911THE MATCHThere never was a time when the world was without fire, but there was a time when men did not know how to kindle fire; and after they learned how to kindle one, it was a long, long time before they learned how to kindle one easily. In these days we can kindle a fire without any trouble, because we can easily get a match; but we must remember that the match is one of the most wonderful things in the world, and that it took men thousands of years to learn how to make one. Let us learn the history of this familiar little object, the match.Fire was first given to man by nature itself. When a forest is set on fire by cinders from a neighboring volcano, or when a tree is set ablaze by a thunderbolt, we may say that nature strikes a match. In the early history of the world, nature had to kindle all the fires, for man by his own effort was unable to produce a spark. The first method, then, of getting fire for use was to light sticks of wood at a flame kindled by natureby a volcano, perhaps, or by a stroke of lightning. These firebrands were carried to the home and used in kindling the fires there. The fire secured in this way was carefully guarded and was kept burning as long as possible. But the flame, however faithfully watched, would sometimes be extinguished. A sudden gust of wind or a sudden shower would put it out. Then a new firebrand would have to be secured, and this often meant a long journey and a deal of trouble.In 1827, John Walker, a druggist in a small English town, tipped a splint with sulphur, chlorate of potash, and sulphid of antimony, and rubbed it on sandpaper, and it burst into flame. The druggist had discovered the first friction-chemical match, the kind we use to-day. It is called friction-chemical because it is made by mixing certain chemicals together and rubbing them. Although Walker's match did not require the bottle of acid, nevertheless it was not a good one. It could be lighted only by hard rubbing, and it sputtered and threw fire in all directions. In a few years, however, phosphorus was substituted on the tip for antimony, and the change worked wonders. The match could now be lighted with very little rubbing, and it was no longer necessary to have sandpaper upon which to rub it. It would ignite when rubbed on any dry surface, and there was no longer any sputtering. This was the phosphorus match, the match with which we are so familiar.What is the main idea of the last paragraph? Early matches were dangerous and awkward. John Walker made the first match. Phosphorus was the key to the modern match. Walker's match was better than what came before.2. What is the main idea of the first paragraph? (SAME STORY AS ABOVE) It took humans a long time to develop the match. Learning how to make fire was a long struggle for humans. The world went for years without adequate fire. We often forget how the match changed the world. 517.21 km what is the nearest 10km? Find the product.(n + 7)(n - 2)n - 5n - 14n + 5n - 14n - 5n + 14 When Amnesty International states that prisoner incommunicado should cease to exist, they mean 1. prisoners must not be tortured2. prisoners should have immediate and regular access to relatives, lawyers, and doctors3. witnesses should be protected from harm4. prisoners need to condemn torture and ill-treatment President george w. bushs national security advisor during his first term was: Let x be a random variable giving the number of aces in a random draw of 4 cards from an ordinary deck of 52 cards. construct a table showing the probability distribution of x solve the equation by completing the square. round to the nearest hundredth if necessary. x^2-6x=20 The main difference between turbojets and rocket engines is the fact that A. turbojets carry their own supply of oxygen as oxidizers. B. turbojets are not dependent on oxygen from the air. C. rocket engines need oxygen from the air. D. rocket engines are not dependent on oxygen from the air. Which of the following statements about this quote from the Texas Almanac is FALSE? a. The quote is biased. b. The quote is factual. c. The quote is credible. d. The quote is from a secondary source. During a remote desktop session, explain the result of opening the network connections window on the remote computer and configuring the network adapter to use a different ip address. Harry rolls a number cube what is the probability that he will roll an even number or a number greater than four What was the intent of the Ryan White CARE Act (now called the Ryan White HIV/AIDS Treatment Extension Act of 2009)? What type of policy as president Obama referring to when he says more people spending more money means more business will be able to hire more workers in the entire economy A flood kills most of a population of ants that live near a river. after the flood, the ant population increases, but its allele frequency is different. what type of effect is this?a.genetic driftb.mass extinctionc.bottleneckd.founder Steam Workshop Downloader