Triangles are polygons with three sides and three angles. There are four types of triangle, but the angles always total 180°.
Equilateral triangles have three sides of equal length and three 60° angles.
Isosceles triangles have 2 sides of equal length and 2 equal angles.
Right angled triangles, as the name suggests, have one 90° (right) angle.
All the sides in scalene triangles are different lengths, and none of the angles are equal.