Sides of Triangles

A triangle is a closed figure with three angles and three sides.  The type of triangle is determined by the length of the sides and the measures of the angles.  The lengths of the sides determine whether the triangle is scalene, isosceles, or equilateral.  The measure of the angles determines whether the triangle is acute, right or obtuse.

A scalene triangle has three sides with different lengths.


Scalene triangles have three angles whose measures are different.

An isosceles triangle has at least two sides that are the same length.


 Isosceles triangles have two angles of equal measure.

An equilateral triangle has three sides the same length.


Equilateral triangles have three angles of equal measure.