The center of a regular octahedron is 3 units away from every vertex. What is the surface area of the octahedron?
We can find the length of any edge as
sqrt ( 3^2 + ^2) = sqrt (18)
The area of one face of the octahedron =
(1/2) (sqrt 18)^2 sqrt (3) / 2 = (9/2)sqrt 3
So....the total surface area = 8 * (9/2) sqrt 3 = 36sqrt 3
+162 
