Answer:
The rate of change in surface area when r = 20 cm is 20,106.19 cm²/min.
Step-by-step explanation:
The area of a sphere is given by the following formula:

In which A is the area, measured in cm², and r is the radius, measured in cm.
Assume that the radius r of a sphere is expanding at a rate of 40 cm/min.
This means that 
Determine the rate of change in surface area when r = 20 cm.
This is
when
. So

Applying implicit differentiation.
We have two variables, A and r, so:



The rate of change in surface area when r = 20 cm is 20,106.19 cm²/min.
Step-by-step explanation:
due to the rules of crossing lines and their angles, the 2 angles opposite of each other must be equal.
so,
7x + 7 = 112
7x = 105
x = 15
Answer is “D” I took the test my self
600,000 + 3,800 = 603,800
45 times .3 =13.5 okkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk