Answer:b
Step-by-step explanation:
X-4 These characters are for >20 rule
The problem is a irrational number
Area=pi times radius^2 so
if area=4pi=pi times r^2
4 times pi=r^2 times pi
divide both sdies by pi
4=r^2
square root
2=radius since legnth cannot be negative
radius=1/2 diamters
2 radius=diameter
2(2)=diameter=4
diameter=4
The radius is 2 and area = r^2*pi so 4*pi gives you 12.56 so the exact answer would be 12.56 and the answer with pi would be 4 times 3.14!