http://www.ck12.org Chapter 1. Basics of Geometry
We classify each triangle by this angle.
Right Triangle:When a triangle has one right angle.
Obtuse Triangle:When a triangle has one obtuse angle.
Acute Triangle:When all three angles in the triangle are acute.
Equiangular Triangle:When all the angles in a triangle are congruent.
Example 3:Which term best describes 4 RSTbelow?
Solution:This triangle has one labeled obtuse angle of 92◦. Triangles can only have one obtuse angle, so it is an
obtuse triangle.
Classifying by Sides
These classifications have to do with the sides of the triangle and their relationships to each other.
Scalene Triangle:When a triangles sides are all different lengths.