http://www.ck12.org Chapter 1. Basics of Geometry
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.
We can also classify triangles by its sides.
Scalene Triangle:When all sides of a triangle are all different lengths.
Isosceles Triangle:Whenat leasttwo sides of a triangle are congruent.
Equilateral Triangle:When all sides of a triangle are congruent.