Types of Triangles
Types of Triangles
There are different types of triangles.
Triangles can be classified by:
Type of Triangle by Lengths of Sides
Triangles are a different type depending on how many sides are the same length (which is also how many angles are equal).
Triangles are equilateral, isosceles or scalene depending on whether 3, 2 or 0 side lengths and angles are equal.
Equilateral Triangles
Equilateral triangles have 3 equal side lengths and angles.

Isosceles Triangles
Isosceles triangles have 2 equal side lengths and angles.

Scalene Triangles
Scalene triangles have 0 equal side lengths and angles.

Type of Triangle by Angles
Triangles are a different type depending on the size of the angles inside the triangle.
Triangles are acute, obtuse or right triangles depending on whether all angles are acute (less than 90°), one angle is obtuse (more than 90°) or one angle is a right angle (90°).
Acute Triangles
Acute triangles have all acute angles (less than 90°).

Obtuse Triangles
Obtuse triangles have one angle that is obtuse (more than 90°, less than 180°).

Right Triangles
Right triangles have one right angle (90°).
