A hemispherical dome with radius=20 feet needs 11 coats of paint, which are 1/100 inch thick ... need to use linear approximation to get the volume of paint needed for the job.

Using linear transformation to get the volume the volume we can use the following formula

V = (2/3) x pi x r^3

40 ft. 11 inches = 480.11 inches

Putting in the formula we getV = (2/3) x pi x (480.11^3 - 480^3)

V = (2/3) x pi x 76049.4 inches V = 159277.54 inches

There are 1728 cubic inches in 1 cubic foot

V = 92.17 cubic feet