If this paper dosent help u solve it on Your own i can walk u through it
Answer:
C) 
Step-by-step explanation:
The formula for area is
A=pi * radius ^2
If the diameter is 40, the radius is 20
Therefore

Answer:
D
Step-by-step explanation:
it is the same exact equation, but backwards. Hope that this helps you and have a great day :)
Answer:

Step-by-step explanation:
Solve for
:

-Subtract
on both sides:


So, therefore, the final answer is
.