A triangle is scalene if all of its sides have different lengths. A triangle is isosceles if two sides have equal measurements with each other. A triangle is equilateral if all three sides have equal measurements with each other. That is how you will explain it to your classmate
First, look at the side lengths a, b, and c, where c is the longest. Then take the sum of a squared and b squared and compare it to c squared. If they are equal, the triangle is a right triangle. If c squared is less than a squared plus b squared, the triangle is acute. If c squared is greater than a squared plus b squared, the triangle is obtuse.