Remember that the interior angles of a triangle add up to 180º.

A **right-angled **triangle has one 90º angle

An **isosceles **triangle has two equal angles

An **equilateral **triangle has three equal angles, each of size 60º

**Example**

Two of the angles in a triangle are 35º and 110º. Which type of triangle is it?

**Answer**

We must first work out the third angle which will be:

180º - (35º + 110º) = 180º - 145º = 35º

So the triangle has angles 35º , 110º, 35º

Two angles are equal so it is **isosceles**.