Types of triangles

The triangles are classified into three types on the basis of lengths of the sides.

Equilateral triangle

A triangle that has all sides of equal length is called an equilateral triangle.

Isosceles triangle

A triangle that has two sides of equal length is called an isosceles triangle.

Scalene triangle

A triangle that has all sides of unequal length is called a scalene triangle.

The triangles are also classified into three types on the basis of the interior angles.

Acute triangle

A triangle that contains three acute angles is called an acute triangle or acute angled triangle.

Right triangle

A triangle that contains a right angle is called a right triangle or right angled triangle.

Obtuse triangle

A triangle that contains an obtuse angle is called an obtuse triangle or obtuse angled triangle.