Question

Thaddeus wants to cover an area around a pond with natural slate stone. If the cost of the slate is $6.50 per square foot, how much will it cost to surround the pond?

Answer 1

Cost of slate path using π: $980.18 (nearest cent)

Cost of slate path using π = 3.14: $979.68

Explanation:

Formula

Area of a circle = πr² (where r is the radius)

First, calculate the area of the slate path by subtracting the area of the pond from the area of the larger circle.

Area of larger circle = π · 8² = 64π ft²

Area of pond (smaller circle) = π · 4² = 16π ft²

⇒ area of slate path = 64π - 16π = 48π ft²

If the cost of the slate is $6.50 per ft² then,

Cost of slate path using π:

⇒ 48π × $6.50 = $980.18 (nearest cent)

Cost of slate path using π = 3.14:

⇒ 48 × 3.14 × $6.50 = $979.68