45-45-90 triangle rule

A 45-45-90 triangle is an isosceles right triangle, meaning its two legs are equal in length and the angles are 45°, 45°, and 90°. The rule states that in such a triangle, the hypotenuse (the longest side opposite the right angle) is always √2 times longer than each leg. For example, if each leg is 1 unit, the hypotenuse will be √2 units. This relationship simplifies calculations and helps easily determine side lengths when working with 45-45-90 triangles in geometry.