Answer:
2c exponent 4 d exponent 4
Using the shell method, the volume is

Each cylindrical shell has radius
(the horizontal distance from the axis of revolution to the curve
); has height
(the vertical distance between a point on the
-axis in
and the curve
).
Compute the integral.

5cm
13^2-12^2=25
C^2 = 25
C = 5
37.5% of 20 is 7.5 so the answer is 37.5%