The roof of a building is shaped like a square pyramid, with a base of 18m by 18m. If the slant height of the roof is 12m and roofing costs 5.75m2, how much will it cost for roofing material?

Answer 1

The lateral surface area of a pyramid (the slanted sides) is the perimeter of the base P multiplied by the slant height H and divided by two, or
A(lateral) = PH/2
Finally multiply by the price per metre^2 to get the price.

Answer 2

so theres 4 sides to a pyramid does that mean each side is 18m?

Answer 3

Exactly!
The perimeter of the square base is therefore 4*18.

Useful information:
"18m x18m " is a short form for "each side of a square is 18m"