Table of Contents Date: 10/17 Topic: Classifying Triangles Description: Using sides and angles to classify triangles. Page: 5

Classifying Triangles Chapter 4 Section 1 Classifying Triangles

Classifications of Triangles BY ANGLES The sides of ∆ABC are The vertices are points The angles are

Classifications of Triangles BY ANGLES Acute Triangle Equiangular Triangle Obtuse Triangle Right Triangle

Example 1: a. Classify the triangle as acute, equiangular, obtuse, or right.

Example 1: b. Classify the triangle as acute, equiangular, obtuse, or right.

Example 2: Classify ∆XYZ as acute, equiangular, obtuse, or right. Explain your reasoning.

Classifications of Triangles BY SIDES Equilateral Triangle Isosceles Triangle Scalene Triangle  

Example 3: If point Y is the midpoint of and WY = 3.0 units, classify ∆VWY as equilateral, isosceles, or scalene. Explain your reasoning.

Example 4: a) Find the measures of the sides of isosceles triangle KLM with base KL

Example 4: b) Find the value of x and the measures of each side of an equilateral triangle ABC if AB = 6x – 8, BC = 7 + x, and AC = 13 – x.

Summary!

Summary!

Summary! 1. Name the vertices of the equilateral triangle.

Summary! 2. Classify ∆ABC by its sides and angles.

Summary! Multiple Choice Which statement is not true? a) In an isosceles triangle, the base is congruent to one of the legs. b) A triangle cannot be scalene and isosceles. c) A triangle cannot be obtuse and contain a 90° angle. d) A triangle can be obtuse and isosceles.

Summary! 4. Classify ∆LMN as acute, equiangular, obtuse, or right.

Summary! 5. Triangle RST is isosceles with ∠S as the vertex angle. If ST = 3x – 11, SR = x + 3, and RT = x – 2, find RT.