Cliff's Notes page on Regular Pyramids, showed me how to solve the Blue Book problem I was stuck on.
The pyramid show above [not drawn to scale] has altitude h and a square base of side m. The four edges that meet at V, the vertex of the pyramid, each have length e. If e = m, what is the value of h in terms of m ?
(A) m ÷ square root of 2
(B) m x square root of 3 ÷ 2
(D) 2m ÷ square root of 3
(E) m x square root of 2
source The Official SAT Study Guide, 2nd edition, p. 401