How much will the walk cost?

Question

A circular pond 26 yd in diameter is surrounded by a gravel path 2 yd wide. The path is to replaced by a brick walk costing $50 per square yard.

Answer 1

The pond's radius is 13 yd and the outer edge of the walkway forms a circle with radius 15 yd.

 

Area of the walkway = π(15)² - π(13)² = π[15² - 13²] = 56π yd²

 

Cost of walkway = ($50/yd²)(56π yd²) = $2800π ≈ $8796.46