A woman 5 ft tall walks at the rate of 3.5 ft/sec away from a streetlight that is 12 ft above the ground. at what rate is the tip of her shadow moving? at what rate is her shadow lengthening? ⇒
Answers
The woman walks at a rate of 3.5 ft/s away from the streetlight. Therefore
[tex] \frac{da}{dt} =3.5 \, ft/s[/tex]
The length of the shadow changes at the rate
[tex] \frac{dx}{dt} [/tex]
Because triangles ACE and BCD are similar (AAA), therefore
[tex] \frac{AC}{BC}= \frac{AE}{BD} \\\\ \frac{a+x}{x} = \frac{12}{5} [/tex]
12x = 5a + 5x
7x = 5a
Therefore
[tex] \frac{dx}{dt} = \frac{5}{7} \frac{da}{dt} = \frac{5}{7} (3.5 \, ft/s) = 2.5 \, ft/s[/tex]
Answer: 2.5 ft/s
The rate at which her shadow is lengthening is 2.5ft/sec
Triangular altitude theorem:To get the rate of her shadow lengthening, we will use the similarity theorem of a triangle.
Find the triangle attached. From the triangle;
[tex]\frac{EA}{AC} =\frac{DB}{BC}[/tex]Substitute the sides as given in the diagram:
[tex]\frac{12}{x+a} =\frac{5}{x}\\12x = 5(x+a)\\ 12x=5x+5a\\7x = 5a[/tex]
Differentiate both sides with respect to t
[tex]7\frac{dx}{dt} = 5\frac{da}{dt} \\7\frac{dx}{dt}=5(3.5)\\7\frac{dx}{dt}=17.5\\\frac{dx}{dt} = 2.5ft/sec[/tex]
The rate at which her shadow is lengthening is 2.5ft/sec
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Related Questions
3.Cornelia spends 2 2/3 hours studying for her big science test. She spent 2/3 of an hour finishing her writing assignment and 1/4 of an hour playing outside. How much time did she spend overall on the three activities?
Answers
8/3 + 2/3 + 1/4 =
10/3 + 1/4 =
40/12 + 3/12 =
43/12 =
3 7/12 hrs <===
Miguel is going for a walk. he takes 3 hours to walk 7.5 miles. what is his speed?
Answers
We want to know how many miles he can walk in 1 hour so, divide both sides by 3 -> 1 hour / 2.5 miles
He is walking at 2.5 mph
divide total distance by time
7.5 miles / 3 hours = 2.5 miles per hour is his speed
Which function represents the graph of f(s)=-4[x] after it is translated 3 units down?
Answers
By the end of the school year, Terry had passed 80% of his science tests. If Terry failed 4 science tests, how many science tests did Terry pass?
Answers
In this case, x = 16 tests passed.
Answer: Terry passed 16 science tests.
Step-by-step explanation: Given that by the end of the school year, Terry had passed 80% of his science tests and Terry failed 4 science tests.
We are to find the number of science tests that Terry passed.
Let x represents the total number of science tests that Terry appeared in.
Since he failed 4 science tests, so the number of science tests that Terry passes is given by
[tex](x-4).[/tex]
Since he passed 80% of his tests, so we get
[tex]80\%\times x=x-4\\\\\\\Rightarrow \dfrac{80}{100}\times x=x-4\\\\\\\Rightarrow \dfrac{4}{5}\times x=x-4\\\\\Rightarrow 4x=5x-20\\\\\Rightarrow 5x-4x=20\\\\\Rightarrow x=20.[/tex]
So, total number of science tests = 20.
Therefore, the number of science tests that Terry passed is given by
[tex]n=20-4=16.[/tex]
Thus, Terry passed 16 science tests.
Roger can run one mile in 10 minutes. jeff can run one mile in 8 minutes. if jeff gives roger a 1 minute head start, how long will it take before jeff catches up to roger? how far will each have run?
Answers
The first three numbers in sequence are 1, 4, and 9. Marie determined that the fourth number in the sequence is 16. Marie’s rule involved multiplication. What rule did she use to determine the fourth number in the sequence? Specific please
Answers
1² = 1
2² = 4
3² = 9,
then 4² = 16 and son and so forth
Help please pre calculus
Answers
put 7.6*10^-1 into the equation to get:
10log(1/7.6*10^-4) = 31.19
What is the perimeter of the triangle shown on the coordinate plane, to the nearest tenth of a unit?
14.6 units
15.5 units
21.0 units
21.6 units
Answers
Right side: This is easiest since it's a vertical line - it's 7 units long.
Top side: If you look carefully, this side is really the hypotenuse of a triangle that is 1 unit tall and 6 units long. Using the Pythagorean Theorem, you can calculate the length of the hypotenuse to be 1^2 + 6^2 = c^2 --> c = 6.1
Left side: just like the top side, this side is the hypotenuse of a triangle that is 6 units tall and 6 units long. Pythagoras again: 6^2 + 6^2 = c^2 --> c = 8.5
Add these three numbers to get the perimeter: 7 + 6.1 + 8.5 = 21.6
if an angle is acute then its measure is 30 degrees true or false
Answers
An acute angle is any angle less than 90 degrees, and while 30 degrees is an example of an acute angle, it is not accurate to say that all acute angles must be 30 degrees.
Explanation:The statement 'If an angle is acute then its measure is 30 degrees' is false. An acute angle is defined as any angle that is less than 90 degrees. While 30 degrees is indeed an example of an acute angle, an acute angle can be any value less than 90 degrees. For example, 45 degrees, 20 degrees, or 1 degree are also acute angles. Therefore, it is not accurate to say that an acute angle must be 30 degrees.
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Find two positive numbers such that the sum of one and the square of the other is 200 and whose product is a maximum.
Answers
If EG=40 and point F is 2/5 of the way between E and G, find the value FG.
The drawing is not to scale.
a. 32
b. 20
c. 16
d. 24
Answers
Point F (EF) = 2/5
EF = 2/5 × 40
EF = 16
EF + FG = EG
16 + FG = 40
FG = 24
d. 24
Solve 5c + 4 = −26.
6
−6
−4.4
3
Answers
Answer:
-6 :))))))))))))))))))
Step-by-step explanation:
What is the difference between 3/7 and 1/14
Answers
3/7 = 6/14
6/14 - 1/14 = 5/14
hope this helps
A prism is named for the shape of its bases.
True
False
Answers
Wikipedia says "Prisms are named for their bases, so a prism with a pentagonal base is called a pentagonal prism."
https://en.wikipedia.org/wiki/Prism_(geometry)
true
Step-by-step explanation:
Hope is helps and good luck
BRAINLIESTTTTTTTT!!!!!!!!!!!!!!!!!!
Answers
For x = 21, f(x) = 105.
To find the average rate of change, subtract 105 - 95.
Then subtract 21 - 11.
Then divide the first difference by the second difference.
Oranges are on sale for $1.59 per pound. Write a funtion as a standard equation and in a funtion notation.
Answers
f(x) = 1.59x
the ordered pair (2 36) is a solution to which equation(s)
A. y=2x^2
B. y=(3x)^2
C. y=7x^2+2
D. y=(x+4)^2
Answers
(2, 36) → x = 2, y = 36
Substitute the value of x and y to the equations of the functions:
A. y = 2x^2
36 = 2(2)^2 → 36 = 8 FALSE
B. y = (3x)^2
36 = (3 · 2)^2 → 36 = 6^2 → 36 = 36 CORRECT
C. y = 7x^2 + 2
36 = 7(2)^2 + 2 → 36 = 7 · 4 + 2 → 36 = 30 FALSE
D. y = (x + 4)^2
36 = (2 + 4)^2 → 36 = 6^2 → 36 = 36 CORRECT
Answer: B. y = (3x)^2 and D. (x + 4)^2
what is the mass of an object that has a force of 100 Newtons and acceleration of 25 m/s2
Answers
m=F/a
m=100/25=4 kg
Mass of an object is 4 kg
Two angles that are complementary __________ form a right angle. 2. angles with a common side and a common vertex ______ form a linear pair. 3. two angles that are supplementary are _______ complementary.
Answers
The width of a poster is 4/5 of its length, It takes 36 ft. of metal framing to frame the poster. Find the dimensions of the poster.
Answers
A bag contains 8 blue marbles, 5 green marbles and 7 red marbles. If Alicia removes two marbles without replacing them, what is the probability that he will choose red, then green?
Answers
To find the probability of choosing a red marble, then a green marble without replacement, multiply the probabilities of the individual events which is 7/76.
Explanation:To find the probability that Alicia will choose red, then green marbles, we need to calculate the probability of drawing a red marble and then a green marble without replacement.
Given that there are 8 blue marbles, 5 green marbles, and 7 red marbles in the bag, the probability of drawing a red marble first is 7/20.
After removing the red marble, there are 19 marbles left in the bag, including 5 green marbles. Therefore, the probability of drawing a green marble second is 5/19.
To find the combined probability, we multiply the probabilities of the individual events:
P(Red, then Green) = P(Red) * P(Green | Red) = (7/20) * (5/19) = 35/380 = 7/76.
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1. Factor the expression 3x^3 + 4x^2 - 15x - 20 Please show work!
Answers
Factor 3x^3 + 4x^2 and -15x - 20 seperately
x^2 (3x + 4) - 5(3x + 4)
(x^2 - 5)(3x + 4) is your answer
hope this helps
The expression 3x^3 + 4x^2 - 15x - 20 can be factored into the form (3x + 4)(x^2 - 5) by grouping terms, factoring out common components, and simplifying.
Explanation:The provided expression to be factored is [tex]3x^3 + 4x^2 - 15x - 20.[/tex]Factoring this involves finding common factors and breaking the terms down until we cannot do so any further.
Group terms that look like they might have common factors: [tex](3x^3 + 4x^2) - (15x + 20).[/tex]Factor out the common factors: [tex]x^2(3x + 4) - 5(3x + 4).[/tex]Notice that we have the binomial of (3x + 4) common between both terms. We can now factor that out: [tex](3x + 4)(x^2 - 5).[/tex]
So, the factored form of the expression is [tex](3x + 4)(x^2 - 5).[/tex]
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Braic equation. two airplanes leave chicago at the same time and fly in opposite directions. if one travels at 490 miles per hour and the other at 470 miles per hour, how long will it take for them to be 4,800 miles apart
Answers
In Indianapolis, the Market Tower has 2/3 as many stories as the Chase Tower. If the Market Tower has 32 stories, how many stories does the Chase Tower have?
Answers
Twenty-five members of the eighth grade class at Park Center Middle School are going to a museum and then to lunch. Each student must pay an entrance fee to the museum and $7.25 for lunch. The total cost for the trip is $443.75. What is the entrance fee for one student?
Answers
1) the cost for lunch, which is given as a rate per student: $7.25/student
2) the cost for the trip which is $443.75 to be divided by the 25 students, so it is $443.75 / 25 = $17.75/student
Now, you can add up those two costs per student to have the total cost per student:
$7.25 + $17.75 = $25.00/student
Answer: $25.00
Answer: $17.75
Step-by-step explanation: $443.75 / 25 = $17.75
Evaluate ab for a = 2 3/4 and b = 4/5
A. 1 1/15
B. 8/15
C. 2 1/5
D. 2/3
Answers
What is the distance between points A and B?
___ units
Answers
we know that
the distance's formula between two points is equal to
[tex]d=\left|xB-xA\right|[/tex]
substitute
[tex]d=\left|1-(-5)\right|[/tex]
[tex]d=6\ units[/tex]
therefore
the answer is
[tex]6\ units[/tex]
The distance between two point [tex]A{\text{ and }}B[/tex] is [tex]\boxed{{\mathbf{6 units}}}[/tex].
Further explanation:
The distance between two points is the modulus of difference of the given two points.
The distance between two points can be found by the distance formula as,
[tex]\left| {B - A} \right|[/tex]
Here, [tex]A{\text{ and }}B[/tex] are the points on the number line.
The distance cannot be negative therefore modulus is applied in the formula.
Step by step explanation:
Step 1:
First we determine the points from the given number line.
It can be observed from the given number line that there are two points one is on the left side of the origin and the second is right side of the origin.
The point [tex]A[/tex] is [tex]- 5[/tex] and the point [tex]B[/tex] is 1.
Step 2:
Now use the distance formula to obtain the distance between the two points [tex]A{\text{ and }}B[/tex].
Here, the value of A is [tex]-5[/tex] and B is 1.
Substitute the value of [tex]A{\text{ and }}B[/tex] to obtain the distance as,
[tex]\begin{aligned}d&= \left| {B - A} \right| \\&= \left| {1 - \left( { - 5} \right)} \right|\\&= 6{\text{ units}}\\\end{aligned}[/tex]
Therefore, the distance between two point [tex]A{\text{ and }}B[/tex] is [tex]6{\text{ units}}[/tex].
Learn more:
Learn more about angle and ray https://brainly.com/question/5144640 Learn more about to determine the equivalent forms of the fraction https://brainly.com/question/952259
Answer details:
Grade: Junior school
Subject: Mathematics
Chapter: Number line
Keywords: Integers, distance, point, number line, units, measurement, origin, negative numbers, positive numbers, right side, left side, difference.
he formula for a trapezoid relates the area A, the two bases, a and b, and the height, h.
A=1/2 h(a+b)
Solve for h.
Answers
A=1/2h(a+b)
2A=1h(a+b)
2A/a+b=h
Hope I helped :)
One car rental company charges $30 per day plus $0.25 per mile driven. a car company charges $40 per day plus $0.10 per mile driven. how many miles must you drive for a one-day rental at the second company to be less expensive than the same rental at the first company? write an inequality to solve.
Answers
let's say x is the miles you drive for a day
the first company's rental charge= $30+$0.25x
the second company's rental charge= $40+$0.10x
Calculate what the x is when two equations are equal to each other:
$30+$0.25x=$40+$0.10x
$0.25x-$0.10x=$40-$30
$0.15x=$10
x=$10/$0.15
x=66.667 miles
at least 66.667 miles. I am not sure though. I'm a little bit tired today, so you might want to check it yourself.
Answer:
66.667 miles
Step-by-step explanation:
Given: One car rental company charges $30 per day plus $0.25 per mile driven.
Second car company charges $40 per day plus $0.10 per mile driven.
To find: how many miles must you drive for a one-day rental at the second company to be less expensive than the same rental at the first company?
Solution: Let the distance driven on a day be x miles.
As per question,
The first rental company will charge [tex]=30+0.25x[/tex]
The second rental company will charge [tex]=40+0.10x[/tex]
Now, we want the rental charges of second company to be less expensive then the first.
So we get the inequality,
[tex]30+0.25x>40+0.10x[/tex]
[tex]0.25x-0.10x>40-30[/tex]
[tex]0.15x>10[/tex]
[tex]x>\frac{1000}{15}[/tex]
[tex]x>66.667[/tex] miles
Hence, at least 66.667 miles should be driven on a day.
The scale on a map indicates that 1 inch corresponds to an actual distance of 95 miles. two cities are 4.5 inches apart on the map. what is the actual distance between the two cities?