math
posted by alley .
Determine the cost of painting the exterior walls and top of a cylindrical wheat silo that is 40 m high and 20 m in diameter. given that each litre of paint costs $7.25 and covers 8 meter square.

SA = (π * r^2) + (2 * π * r * h)
Divide the total area by 8. Multiply by 7.25.