Posted by timmy on Wednesday, February 29, 2012 at 4:54pm.
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?

math  MathMate, Wednesday, February 29, 2012 at 9:34pm
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. 
math  anonymous, Wednesday, February 29, 2012 at 10:36pm
so theres 4 sides to a pyramid does that mean each side is 18m?

math  MathMate, Thursday, March 1, 2012 at 8:48am
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"