Lesson 2 of the PreAlgebra Geometry Unit

1. Basic Geometry Unit 9.4 – Triangles

4. Types of Triangles By Angles In an acute triangle , all the angles are acute. In an obtuse triangle , one angle is obtuse. In a right triangle , one angle is right. In an equiangular triangle , all the angles are congruent.

5. Types of Triangles By Sides No two sides of a scalene triangle are congruent. At least two sides of an isosceles triangle are congruent. All the sides of an equilateral triangle are congruent.

6. Classify each triangle by its angles and by its sides. 60° 60° 60° 60° 30°