One way of classifying triangles is by their number of congruent sides. A triangle that has no sides congruent is called a scalene triangle. A triangle that has 2 sides congruent is called an isosceles triangle and a triangle that has all 3 sides congruent is called an equilateral triangle.
Another way of classifying triangles is by their angle measures. A triangle that has 3 acute angles is called an acute triangle. A triangle that has 1 obtuse angle is called an obtuse triangle. A triangle that has 1 right angle is called a right triangle and a triangle that has all 3 angles congruent is called an equiangular triangle.
