GEOMETRY
posted by JOY .
FIND THE LATERAL AREA OF A RIGHT PYRAMID WHOSE SLANT HEIGHT IS 18mm AND WHOSE BASE IS A SQUARE WITH AN AREA 121mm^2

The length of the base (b) of each triangular side is sqrt 121 = 11 mm. The height (h) of each triangle is the 18 mm slant height. Therefore each of the four sides has an area of
1/2 (base)*(height) = 11*18/2 = 99 mm^2
The total lateral area is therefore 4*99 = 396 mm^2 
THANK YOU SO MUCH!