# Analyze and Classify Triangles

Videos to help Grade 4 students learn how to analyze and classify triangles based on side length, angle measure or both.

Common Core Standards: 4.MD.7

## New York State Common Core Math Module 4, Grade 4, Lesson 13

NYS Math Module 4 Grade 4 Lesson 13 Application Problem

Fold Triangles A, B, and C to show their lines of symmetry. Use a straightedge to trace each fold. Discuss with your partners the relationships of symmetric shapes to angles and side lengths.

NYS Math Module 4 Grade 4 Lesson 13 Problem 2

Measure and classify triangles by side length and angle measure.

NYS Math Module 4 Grade 4 Lesson 13 Problem Set

Types of Triangles: Equilateral, Isosceles, Scalene, Acute, Right, Obtuse

1. Classify each triangle by its side lengths and angle measurements. Circle the correct names.

Lesson 13 Problem Set

2. ABC has one line of symmetry as shown. What does this tell you about the measures of ∠A and ∠C ?

3. DEF has three lines of symmetry as shown.
a. How can the lines of symmetry help you figure out which angles are equal?
b. DEF has a perimeter of 30 cm. Label the side lengths.

NYS Math Module 4 Grade 4 Lesson 13 Homework

1. Classify each triangle by its side lengths and angle measurements. Circle the correct names. Use a ruler and a right angle template to prove your classifications.

5. Can a triangle have more than one obtuse angle? Explain.