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Igoryamba
2 years ago
5

It is given that A is directly proportional to r2 and r> 0. When r=5, A=75.

Mathematics
1 answer:
torisob [31]2 years ago
3 0

Answer:

see explanation

Step-by-step explanation:

Given A is directly proportional to r² then the equation relating them is

A = kr² ← k is the constant of proportion

To find k use the condition when r = 5, A = 75 , then

75 = k × 5² = 25k ( divide both sides by 25 )

3 = k

A = 3r² ← equation of proportion

(a)

when r = 4, then

A = 3 × 4² = 3 × 16 = 48

(b)

when A = 147 , then

147 = 3r² ( divide both sides by 3 )

49 = r² ( take the square root of both sides )

r = \sqrt{49} = 7

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Nesterboy [21]

The average rate of change of the function at the interval is -8

<h3>How to determine the average rate of change?</h3>

The table that completes the question is added as an attachment


From the table, we have:

f(5) = -26

f(3) = -10

The average rate is then calculated as:

Rate = (f(5) - f(3))/(5 -3)

This gives

Rate = (-26 + 10)/(5 -3)

Evaluate

Rate = -8

Hence, the average rate of change of the function is -8

Read more about average rate of change at:

brainly.com/question/8728504

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7 0
2 years ago
Solve for the given variable
Aleks04 [339]

Answer:

42 degrees

Step-by-step explanation:

Angles in a triangle equal 180

180-(37+90)=53

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180-53=127

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126=3b

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42 degrees

7 0
3 years ago
Solve: x^2 – 16x + 63 &lt; 0 ​
marysya [2.9K]

Answer:

7 < x < 9

Step-by-step explanation:

x^2 – 16x + 63 < 0

this is a parabola that opens up.

The parabola will be < 0 for values between the roots.

to picture this see the graph below.

Factor

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8 0
3 years ago
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Elena L [17]
The answer would be the 3rd choice because this is a translation
8 0
3 years ago
The formula T= 2pi sqrt(L/32) relates the time, T, in seconds for a pendulum with the length, L, in feet, to make one full swing
tester [92]

The length of pendulum is 2.485 feet

<h3><u><em>Solution:</em></u></h3>

Given that,

The formula T= 2pi sqrt(L/32) relates the time, T, in seconds for a pendulum with the length, L, in feet, to make one full swing back and forth

<u><em>Therefore, the given formula is:</em></u>

T=2\pi \sqrt{\frac{L}{32} }

We have to find the length of pendulum that makes one full swing in 1.75 seconds

So the modify the given equation to find "L"

T=2\pi \sqrt{\frac{L}{32} }\\\\ \sqrt{\frac{L}{32} }=\frac{T}{2 \pi}\\\\\text{Taking square root on both sides }\\\\\frac{L}{32} = \frac{T^2}{4 \pi^2}\\\\L = \frac{T^2}{4 \pi^2} \times 32\\\\L = \frac{T^2}{\pi^2 } \times 8

Substitute T = 1.75 seconds and \pi = 3.14

L = \frac{1.75^2}{3.14 \times 3.14} \times 8\\\\L = \frac{3.0625}{9.8596} \times 8\\\\L = 2.485

Thus length of pendulum is 2.485 feet approximately

7 0
3 years ago
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