Diagonal of the Square

A square has two diagonals. Each one is a line segment drawn between the opposite vertices (corners) of the square. The diagonals have the following properties:
The two diagonals are congruent (same length).
Each diagonal bisects the other. In other words, the point where the diagonals intersect (cross), divides each diagonal into two equal parts
Each diagonal divides the square into two congruent isosceles right triangles. Because the triangles are congruent, they have the same area, and each triangle has half the area of the square.

Using this software you can calculate easily the diagonal of the square by typing the two bases.