Special Right Triangle Formulas

30 - 60 - 90 Right Triangle

A right triangle having angles of 30 degrees, 60 degrees, and 90 degrees.

Right Isosceles Triangle : 45 - 45 - 90

A right triangle with two congruent legs, a right angle and 2 congruent angles that both equal 45 degrees.

Formula for Right Isosceles Triangle: 45-45-90

Both legs = eachother

Formula for 30-60-90

Find "a" by putting whatever # is given on either the long leg, short leg, or hypotenuse. Then plug in "a" to x and y.

30-60-90 Right Triangle Rule

The longest side will be opposite the largest angle, and the shortest side opposite the smallest angle. (The side opposite the 30 degree angle will have the shortest length. The side opposite the 60 degree angle will be √ 3 times as long, and the side opposite the 90 degree angle will be twice as long. )