There is a special relationship among the measures of the sides of a triangle.
triangle is a commonly encountered right triangle whose sides are in the proportion . The measures of the sides are , , and .
In a triangle, the length of the hypotenuse is times the length of a leg.
To see why this is so, note that by the Converse of the Pythagorean Theorem , these values make the triangle a right triangle.
Note that an isosceles right triangle must be a triangle.