A right square pyramid has a surface area of 65.5m² and a base length of 3.5 m. Determine the height of the pyramid
the lateral area consists of 4 triangles, each with area
1/2 * 3.5 * √(h^2 + (3.5/2)^2)
if you include the base area of 3.5^2, then you have
3.5^2 + 7√(h^2 + 1.75^2) = 65.5
so now just solve for h. I get h=7.4 m