Alternatively calculate the side lengths, if $c$ is the largest and $c^2=a^2+b^2$ it is a right triangle, otherwise it isn't. read more
If the sum of the squares of two of the sides= the square of the third side,, then you have a right triangle. Example: a triangle's sides are 5, 12, and 13. If you square all 3 sides, you get 25, 144, and 169. read more
In this lesson, you will learn how to classify a triangle by using the Pythagorean Theorem. read more