Given: A S+pecial right triangle with 45-45-90 angles. Since the two angles are equal and are both 45 degrees, the two sides opposite each angle are also equal. So if one leg is 1 unit, then the other leg is also 1 unit and the hypotenuse can be determined using the Pythagorean Theorem:
c^2 = a^2 + b^2
c^2 = 1^2 + 1^2
c = √2