Question

if asphalt costs $0.78 per square foot, determine, to the nearest cent, the cost of paving the shaded circular road with center O, an outside radius of 50 feet, and an inner radius of 36 feet.
(the big circle is shaded)

Answer 1

A = pi ^ r^2

A = 3.14 * 50^2
A = 3.14 * 2500
A = 7,850 square feet

Find the area of the smaller circle. Then subtract the smaller area from the larger area. Multiply the difference by $0.78

I'll be glad to check your answer.

Answer 2

2590.33