radius of circle

Question

In a circle a 90 degree sector has an area of 64 ii ft2.  What is the radius of the circle?

Answer 1

Total angle of circle = 360 degrees

The circle have four 90 degree sectors.

Area of circle = pi*r^2

Area of given sector = 64

so pi*r^2 = 64*4

22/7*r^2 = 256

r^2 = 256*7/22

r^2 = 128*7/11

r^2 = 896/11

r^2 = 81.4

r = sqrt 81.4

r = 9.02 ft

radious of given cifcle = 9.02 ft