Mathematics College

the top of an auto piston is a circle with a diameter measuring 8.4 centimeters . what is the area of the top piston ?

Answers

Answer 1
Radius = Diameter /2 

So, Radius = 8.4/2 or 4.2 

4.2^2 = 17.64. 

17.64 x pi = 55.39 sq cm. 

cm because we are being consistent with the units of measurement already in use.
Answer 2

area of a circle = PI x r^2

r = 8.4/2 = 4.2

using 3.14 for PI

 area = 3.14 x 4.2^2 = 55.3896 square cm

 round answer as needed

Related Questions

what is the exponent used in cubing a number

Answers

Cubing a number means raising that number to the third power.

So, the answer is 3.

Let a and b be the solutions of the quadratic equation $2x^2 - 8x + 7 = 0. Find 1/(2a)+(1/2b).

Please help me!

Answers

Hello,

[tex]2x^2-8x+7=0\\ x^2-4x+ \frac{7}{2} =0\\ So\ a+b=4\ and\ \frac{a+b}{2} =2\ (x^2-(a+b)x+a*b=(x-a)(x-b)\ )[/tex]

what is 77.0 divided by 200

Answers

77/200 = 0.385

hope this helps
When you get your handy dandy calculator out...
77/200 comes out to equal 0.385

A tank can be filled by one pipe in four hours and by a second pipe in six hours; and when it is full, the tank can be drained by a third pipe in three hours. If the tank is empty and all three pipes are open, in how many hours will the tank be filled?
A. 8 hours
B. 12 hours
C. 24 hours

Answers

I think its B.  In 12 hrs, the tank will be filled with
all 3 pipes open
The correct answer would be 
B) 12 hours.

In October Greg and Thomas had the same amount of money in their savings account in November Greg deposited $120 into his account Thomas increased the money in his account by 20% when they compare their bounces they found out they were still equal

Answers

assume the amount of money they both deposited in october is m.
in november, greg deposited 120$, so the total amount in his account became m+120
thomas increased his account by 20%, this meams that the amount of money in his account became: m+0.2m
since both values are still equal, we will equate the two equations and solve for m:
m+120 = m+0.2m
0.2m = 120
m = 600$

Which of the following gives an example of a set that is closed under multiplication? CHOOSE ALL THAT APPLY !!!! 15 PTS

A. The product of an even number and an even number


B. The product of 0 and 0


C. The product of a negative number and a negative number


D. The product of a perfect square and a perfect square

Answers

a because the square root would be equal so the correct response would be a

Find parametric equations for the line through the point ( 0,3,2 ) that is perpendicular to the line ! ! x =1+t , ! ! ! y = 3−t , ! ! z = 4t , and intersects this line. (use the parameter t ).

Answers

wgats the choices????????????????????

So is the answer - least is the negative first, them zero, them the positive?

Answers

Yes. That’s the order.

The decimal equivalent to the binary number 0 0 0 1 0 1 1 0 is ______________.

Answers

this would be

1 + 2^1 + 2^3  =  11 in decimal 

Ceremonies help individuals cope with loss as they facilitate the grieving process. Please select the best answer from the choices provided. T F

Answers

this answer is true ceremonies help deals with loss

Answer:

True

Step-by-step explanation:

Ceremonies do help individuals cope with loss as they facilitate the grieving process.

Find f(5) for f(x). ... .. ... ....

Answers

Plugging 5 in for x, we get (1/9)*3^5=(1/9)*243 due to that in PEMDAS, exponents come before multiplication, Next, we multiply the two to get 243 as our answer
I believe the answer is B

is 11:17 equivalent to 17:11

Answers

Answer:

  No

Step-by-step explanation:

If these are time values, ...

  11:17 is about 5 hours 54 minutes earlier than 17:11.

___

If these are ratios, ...

  11/17 is less than 1, whereas 17/11 is greater than 1

Each is the inverse of the other.

F(x)=x-2/x^3+x find the domain

Answers

hello : 
f  exist : x^3+x ≠ 0 
but :  x^3+x = 0
x (x²+1) =0
x= 0        x²+1 = 0    ( x² = -1  no reals solutions )
the domain is : D = ]-∞,0[ U  ]0,+∞[

Train A and train B leave a central station at the same time. They travel the same speed, but in opposite directions, with train A heading towards station A, and train B heading towards station B. Train A reaches station A after 4 h. Train B reaches station B after 312 h. Station A and Station B are 562.5 mi apart. What is the rate of the trains? Enter your answer in the box.

Answers

the answer is 75 mph i took the test and it said 75 not 1.78

Answer:

its 75 i did the math a calaculator

Step-by-step explanation:

Suppose that it costs ​$25 to place a classified advertisement in the​ newspaper, plus ​$3 for each line. Then the cost to place an ad x lines long is given by y​ dollars, where y=3x+25. Express an ordered pair the fact that a 2 line ad cost $31

Answers

substitute 2 for x:
y = 3(2) + 25

y = 6 + 25

y = 31

in (x,y) form:
(2, 31)

use multiplication and the Distributive property to find the quotient
70 divided by 5 =

Answers

once you divide 70 by 5 your answer will be 14

5 minus the product of V and 7

Answers

" the product " means multiply

5 - 7V <== ur expression

2) Mr. Somers had twenty pieces of metal that were all the same length. If each piece of metal was 3 1/5 inches long and he put them side by side, what would be the total length of all the pieces together?

Answers

You would do 20 • 3=60 and the you would add 20 • 1/5=4 so, your total is 64in.

3/5 of 40 dollar restaurant

Answers

40 * 3/5
120/5
24

Hope this helps!
To find the answer times: 3/5 x 40 = 24

wes has six errands to run (picking up the dry cleaning, going to the grocery store, getting gas, going to the bank, going to the library, and going to the video store). he only haves time to run 3 errands this afternoon. how many different combinations of three errands could he choose to run?

Answers

if you did 1*2*3*4*5*6 it's 720

Answer: 120 different combinations  .

Step-by-step explanation:

The combination of n things taking m things at a time is given by :-

[tex]C(n,m)=\dfrac{n!}{m!(n-m)!}[/tex]

Given : The total numbers of errands = 6

Now, the combination of 6 errands taking 3 at a time is given by :-

[tex]C(6,3)=\dfrac{6!}{3!(6-3)!}\\\\=\dfrac{6\times5\times4\times3!}{3!}=120[/tex]

Hence, he could choose to run 120 different combinations of three errands .

Need help with number 6. Also could you tell me if I did number 5 right? Thanks

Answers

check the picture below.

thus

[tex]\bf \stackrel{0}{h}=-16t^2+64\implies 0=-16t^2+64\implies 16t^2=64\implies t^2=\cfrac{64}{16} \\\\\\ t^2=4\implies t=\sqrt{4}\implies t=\stackrel{seconds}{2}[/tex]

as far as 5, is correct, however

[tex]\bf \textit{using the pythagorean theorem}\\\\ c^2=a^2+b^2\implies c=\sqrt{a^2+b^2}\qquad \begin{cases} c=hypotenuse\\ a=adjacent\\ b=opposite\\ \end{cases} \\\\\\ c=\sqrt{15^2+8^2}\implies c=\sqrt{289}\implies c=17[/tex]

Over last week,the daily low temperature in degrees Fahrenheit have been -4,6.2,18 1/2,-5.9,-1/4,and1.75.list these numbers in order from least to greatest

Answers

-5.9
-4
-1/4
.2
1/2
1.75
18
-5.9, -4, -1/4, 1/2, 1.75, 6.2, 18

Maree is 8 years older than Aaron.
Aaron is twice as old as Rick.
All their ages add up to 28.
What are their ages?
Maree is
Aaron is
Rick is




Answers

maree is 16
Aaron is 8
Rick is 4

what is the answer? this is hard

A couple has 4 children. what is the probability they would have four boys

Answers

.,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,1/4

The function d(x) =3x +2 determine how many donuts need to be purchased for a meeting, where x is the number of people at the meeting. The office manager uses h(d(x)) to find the amount of money to bring for the donuts purchase. The function h(x) = 2x + 7 . Solve for how much money to bring when there are 8 people In the meeting.
A.25
B.26
C.52
D.59

Answers

The answer is C... Hope I helped:-)

Evaluate. 7^2 - 3 + 9 × 8 ÷ 2

w =

Answers

7^2 - 3 + 9 x 8 / 2
49 - 3 + 9 x 8 / 2
49 - 3 + 72/2
49 - 3 + 36
46 + 36
82

w = 82

Find the mean of the data set. If necessary round to nearest tenth. 18.1,17.9,16.8,18.7,15.1

Answers

Finding the mean means find the average so we add are data set up and then divide it by the the amount we have in our data set. So

[tex]\frac{18.1+17.9+16.8+18.7+15.1}{5} = 17.32[/tex]

And if we round to the nearest tenth it would be 17.3

Use this equation to find dy/dx. 3y cos x = x2 + y2

Answers

Given: 3y cos x = x² + y²

Define [tex]y' = \frac{dy}{dx} [/tex]

Then by implicit differentiation, obtain
3y' cos(x) - 3y sin(x) = 2x + 2y y'
y' [3 cos(x) - 2y] = 2x + 3y sinx)

Answer:
[tex] \frac{dy}{dx} = \frac{2x+3y \, sin(x)}{3cos(x)-2y} [/tex]

what is 150% as a fraction

Answers

150% means 150 out of 100 so find the GCF of both 150 and 100 and that would be 50 since it can go into both 150 and 100.

divide both the numerator and denominator by GCF

Simplify 

Answer: 3/2
To write .150 as a fraction you have to write .150 as the numerator and put 1 as the denominator. Now you multiply numerator and denominator by 10 as long as you get in numerator the whole number.
.150 = .150/1 = 1.5/10 = 15/100

And finally we have: 
.150 as a fraction equals 15/100

Any proposed solution of a rational equation that causes a denominator to equal​ _______ is rejected.

Answers

Answer:

Any proposed solution of a rational equation that causes a denominator to equal​ __ZERO__ is rejected.

Step-by-step explanation:

We will show this statement is true by an example:

Consider the expression :  [tex]\frac{x}{x-4}=\frac{x}{x-4}+4[/tex]

Now, solved the rational expression and check its proposed solution

[tex]\frac{x}{x-4}=\frac{x}{x-4}+4[/tex]

x cannot equal to 4, as it makes  both denominators equal to zero.

Multiply both the sides by (x-4),

[tex]\left ( x-4 \right )\cdot \frac{x}{x-4}=\left (x-4 \right )\cdot\left ( \frac{x}{x-4}+4  \right )\\[/tex]

Now, use the distributive property on Right hand side,

[tex]\left ( x-4 \right )\cdot \frac{x}{x-4}=\left (x-4 \right )\cdot \left ( \frac{x}{x-4} \right )+\left (x-4 \right )\cdot 4\\[/tex]

Simplify the above expression,

[tex]x=x+4x-16[/tex]

Combine like terms,

[tex]x-x-4x=-16[/tex]

[tex]-4x=-16[/tex]

Divide both sides by -4, we get

[tex]\frac{-4x}{-4}=\frac{-16}{-4}[/tex]

[tex]x=4[/tex].

As we know that x cannot equal to 4, replacing x=4 in the original expression causes the denominator equal to 0.

Check the solution: [tex]\frac{x}{x-4}=\frac{x}{x-4}+4[/tex]

Substitute the value of x=4 in the original expression,

[tex]\frac{4}{4-4}=\frac{4}{4-4}+4[/tex]

[tex]\frac{4}{0}=\frac{4}{0}+4[/tex]

Thus, 4 must be rejected as the solution, and the solution set is only 0.












Final answer:

A proposed solution of a rational equation that causes a denominator to equal zero is rejected because division by zero is not possible.

Explanation:

Any proposed solution of a rational equation that causes a denominator to equal zero is rejected. When the denominator of a rational equation is zero, the fraction becomes undefined because division by zero is not possible. In mathematics, division by zero is an undefined operation.

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