Ooo, this one's a quick one! To solve this, you must use the area of a circle formula, which is a=πr².
NOTE: The 20in you see in this picture, is known as the circumference, but the radius is HALF of the diameter, so our radius or "r", is 10!
Plug it in!
π(10²)
Do 10²!
=100
Now finish the equation by multipling your 400 by your π!
ANSWER: 314.159265359
(If you were instructed to round, this is not the rounded answer)
