Types of triangles

 

Isosceles Triangle

An isosceles triangle has two edges of the same length.

Two of its vertex angles must also be the same size.

It has one line of symmetry.

Isoceles triangles are found in circles

 

Equilateral Triangle

An equilateral triangle has all of its edges of the same length.

All of its vertex angles must also be the same size (60° )

It has three lines of symmetry.

 

 

Scalene Triangle

A scalene triangle has all its edges of different lengths.

All of its vertex angles must also be of different sizes.

It has no symmetry.

 

 

Acute Triangle

An acute triangle has no vertex angle greaterthan 90°.

It is either an isosceles or scalene triangle.

 

Obtuse Triangle

An obtuse triangle has one vertex angle greater than 90°.

It is either an isosceles or scalene triangle.

 

Right-angled Triangle

A right-angled triangle has one vertex angle equal to 90°.

It is either an isosceles or scalene triangle.

 

Angles in a triangle