Circle a has an area of 500 in.². the diameter of the circle b is three times the diameter of circle a. estimate the area of circle b.

R^2π=500in^2
r^2=500 in^2/π
r=(500 in^2/π)^(1/2)= 12.62 in
plug it in:
db=3da=3(2(12.62))= 75.69
r of b = 75.69/2=37.85in
A of b = (37.85in)^2π = 8.22 in^2

Were is the diagram?