An acute triangle is a triangle with 3 acute angles.
A right triangle is a triangle with 1 right angle.
An obtuse triangle is a triangle with 1 obtuse angle.
- A scalene triangle is a triangle with no equal side lengths.
An isosceles triangle is a triangle with (at least) 2 angles of equal measure and (at least) 2 sides of equal length.
An equilateral triangle is a triangle with 3 sides of equal length.
An equilateral triangle can also be classified as an isosceles triangle.
A triangle with an obtuse angle is an obtuse triangle.
A triangle with two angles of the same measure is an isosceles triangle.
So, a triangle with angle measures of 10°, 160°, and 10° is an obtuse isosceles triangle.
A triangle with a 90° angle is a right triangle.
A triangle with no equal side lengths is a scalene triangle.
So, a triangle with a 90° angle and side lengths of 3 inches, 4 inches, and 5 inches is a right scalene triangle.
5th Grade Math - Classify Shapes Lesson
