Acube has lengths of 6 inches what is the length of the diagnol

The diagonal's length is about 3.5 inches; to solve, use the Pythagorean theorem (a^2 + b^2 = c^) to determine the length of the diagonal using one of the two triangles it forms by cutting the square in half. One triangle has three sides: 6 in, 6 in, and the unknown diagonal.
6^2 + 6^2 = c^2 Plug in the known sides
36 + 36 = c^2 Simplify
72 = c^2 Simplify
~3.5 = c Take the square root of both sides