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:
Two of the angles in a triangle are 34º and 112º. Which type of triangle is it?
We must first work out the third angle which will be:
180º - (34º + 112º) = 180º - 146º = 34º
So the triangle has angles 34º, 112º, 34º
Two angles are equal so it is isosceles.
Now, let's put these rules into practice.