math
posted by brooke on .
if a square pyramid has a base side length of 6.3 m and a slant height of 4 m. find its surface area

Consider one of the four isosceles triangles.
drawing a line from the top vertex to the midpoint of the base gives you a rightangled triangle whose height can be found by
h^2 + 3.15^2 = 4^2
h = √6.0775
the surface area of the four triangles is then
4*(1/2)(6.3)51√6.0775
= 31.06
if you want to include the area of the base to your answer, add 6.3^2