A right triangle
is a triangle with one right angle (an angle of 90°). Its hypotenuse is the side opposite the right angle.
In a right triangle, with sides (legs) a and b, and hypotenuse c, then c²=a²+b².
The square of the hypotenuse is the sum of the squares of the legs
Apply the Pythagorean Theorem: If you know any two of the sides in a right triangle, you can find the dimensions for the missing side using the Pythagorean Theorem.
In a right triangle you know:
The legs are 12 and 9 long.
Calculate the triangle area: