Section 4 1 Classifying Triangles EQ How are

Section 4. 1 : Classifying Triangles EQ: How are the angle measures of triangle related?

Vocabulary, Questions, Description of Examples Definitions, Answers, Examples and Diagrams Three-sided polygon B Written ∆ABC Triangle A Three acute angles (angles with degree less than 90) Acute Triangle 3 congruent acute angles Equiangular Triangle C

Vocabulary, Questions, Description of Examples Definitions, Answers, Examples and Diagrams 1 obtuse angle (angle > 90) Obtuse Triangle 1 right angle (angle = 90) Right Triangle

Example 1: a) Classify the triangle as acute, equiangular, obtuse, or right. 3 acute angles that are all equal Equiangular b) Classify the triangle as acute, equiangular, obtuse, or right. 1 obtuse angle Obtuse Triangle

Example 2: Classify ∆XYZ as acute, equiangular, obtuse, or right. Explain your reasoning. Right Triangle ∠XYW + ∠WYZ = 90° 40° + 50° = 90°

You Try! 3 acute angles = acute triangle 1 right angle = right triangle 1 obtuse angle = obtuse triangle

Vocabulary, Questions, Description of Examples Definitions, Answers, Examples and Diagrams 3 congruent sides Equilateral Triangle At least 2 congruent sides Isosceles Triangle No congruent sides Scalene Triangle

You Try! 3 congruent sides = equilateral triangle No congruent sides = scalene triangle 2 congruent sides = Isosceles 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. Scalene – no sides are equal

Example 4: •

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

You Try! • 1. Classify each triangle. (Draw a picture to help!) B Isosceles triangle A C

You Try! • 1. Classify each triangle. (Draw a picture to help!) D Right triangle E F

You Try! • 1. Classify each triangle. (Draw a picture to help!) K Equilateral triangle J L

You Try! • 1. Classify each triangle. (Draw a picture to help!) N No sides equal = scalene triangle M P

You Try! • 1. Classify each triangle. (Draw a picture to help!) R S 1 obtuse angle = obtuse triangle Q