Geometry
posted by helen .
Find the length of d in simplest radical form of he diagonal of a cube with sides of s units.

diagonal of a square is √(s^2+s^2) = s√2
diagonal of a cube is √(s^2+s^2+s^2) = s√3
Think of it as the hypotenuse of a triangle perpendicular to the base, where one leg is the base diagonal (s√2) and the height is s, making the hypotenuse
h^2 = 2s^2 + s^2 = 3s^2 
each triangle is a 45 degrees45 degrees90 degrees.find the value x