4.1 Classifying Triangles Unit 2 Chapter 4

Sides, Vertices, and Angles

Triangle Classifications by Angles

Example 1 A) Classify the triangle as acute, equilangular, obtuse, or right.

Example 1 B) Classify the triangle as acute, equilangular, obtuse, or right.

Example 1 C) The frame of this window design is made up of many triangles. 1) Classify ∆ACD. 2) Classify ∆ADE.

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

Classifications of Triangles by Sides To indicate that sides of a triangle are congruent, an equal number of hash marks are drawn on the corresponding sides.

Example 3 The triangle truss shown is modeled for steel construction. Classify ∆JMN, ∆JKO, and ∆OLN as equilateral, isosceles, or scalene.

Example 4 If point Y is the midpoint of VX and WY = 3.0 units, classify ∆VWY as equilateral, isosceles, or scalene. Explain your reasoning.

Example 5 A) Find the measures of the sides of isosceles triangle KLM with base KL

Example 5 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.

Foldable time! Use your notes to fill out the foldable. You may use markers, colored pencils, whatever you would like!