Question

The lateral edge of a pyramidal church spire is 61 ft. Each side of the

octagonal base is 22 ft. What will be the cost of painting the spire at

$0.025 a square foot?

Answer 1

Lateral area $=\dfrac{1}{2}$ Perimeter of the base $\times$ Slant height

Lateral area $=\dfrac{1}{2}(8\cdot22)\times61=5368 ({ft}^2)$

$$Cost=\$0.025/{ft}^2\cdot5368{ft}^2=\$134.20$$

The cost of painting the spire is $134.20.