One of the special right triangles which we deal with in geometry is an isosceles right triangle. These triangles are also known as 45-45-90 triangles (so named because of the measures of their angles). There is one theorem that applies to these triangles. It is stated below.

In a 45-45-90 triangle, the measure of the hypotenuse is equal to the measure of a leg multiplied by SQRT(2).

The following figure presents the theorem in graphical terms.