Question 758137
Volume of a right circular cylinder
= Pi r^2 h
Ist Silo = Pi *6^2 * 40 = 4523.89 cuft
2nd Silo = Pi * 7^2 * 50 = 7696.90 cuft
3rd Silo = Pi * 9^2 * 60 = 15268.14 cuft
Total Volume = 27488.93 cuft.

Surface Area of a right circular cylinder
= Pi r^2 + 2 Pi r h (Assuming only the top
of the silo needs painting.)
1st Silo= Pi * 6^2 + 2*Pi*6*40 = 1621.06 ft^2
2nd Silo = Pi * 7^2 + 2+Pi*7*50 = 2353.05 ft^2
3rd Silo = Pi * 9^2 + 2 * Pi * 9 * 60 = 3647.39 ft^2
Total Surface Area = 7621.5 ft^2
Divided by 100 sq ft = 76 215 
Requiring 77 quarts of paint.