Classifying Triangles by Angles and Sides Geometry

Today’s Standard and EQ: M4G1. Students will define and identify the characteristics of geometric figures through examination and construction. a. Examine & compare angles in order to classify & identify triangles by their angles. EQ: In what ways can triangles be classified?

Today we will be learning how to classify triangles according to length of sides and measurement of the angles.

First we will learn to classify by the ANGLES

Right triangles have ONE right angle

Acute Triangles have three acute angles

Obtuse Triangles have ONE obtuse angle

Now You Try! Look at each triangle and decide if it is a RIGHT, ACUTE, or OBTUSE triangle. 2 1 6 4 3 5

We will now learn to classify triangles by their sides.

Equilateral Triangles have 3 equal sides If you collapsed all of the sides they would form a line.

Isosceles Triangles have 2 equal sides.

Scalene Triangles have NO equal sides

Now You Try! 2 1 6 4 3 5 Look at each triangle and decide if it is an EQUILATERAL, SCALENE or ISOCELES triangle. 2 1 6 4 3 5

Every triangle can be classified in two ways! Remember… Every triangle can be classified in two ways! Measure of the Angles Length of the Sides Right triangles have one right angle Equilateral triangles have three equal sides Acute triangles have three acute angles Isosceles triangles have two equal sides Obtuse triangles have one obtuse angle Scalene triangles have NO equal sides

You have now learned that triangles can be classified by either their sides or their angles.