How do you classify triangles? Triangles can be classified by the length of their sides or by angle measure. You can also combine side length and angle measure and have an acute isosceles triangle, a right isosceles triangle, and an obtuse isosceles triangle. Please see the chart below. Check out this link to test your knowledge of triangles. Types of triangles
Scalene triangle |
Three different side lengths
Three different angle measures |
Isosceles triangle |
At least two congruent sides
At least two congruent angles |
Equilateral triangle |
Three congruent sides
Three congruent angles The angle measure equals 60 degrees |
Acute triangle |
Triangle with three angles that measure less than 90 degrees |
Obtuse triangle |
Triangle with one angle greater than 90 degrees |
Right triangle |
Triangle with one right angle ( 90 degrees) The other two angles are complementary |