The area of one lateral face of a right pyramid with an equilateral triangular base is 75 square meters. If the slant height is 30 meters, what is the length of the side of its base, in meters?
The face forms a triangle.....Area of triangle = (1/2) base * height
The slant height is the height of the triangle....so....
75 = (1/2) base *(30)
75 = 15 * base divide both sides by 15
5 m = base
So.....a side of the base = 5m
+166 
