What are the two main ways to classify triangles?

By their angles and by their sides

Explain the difference between an acute, right, and obtuse triangle.

An acute triangle has all angles less than 90 degrees, a right triangle has one 90 degree angle, and an obtuse triangle has one angle greater than 90 degrees.

A triangle has angles measuring 30 degrees and 60 degrees. What is the measure of the third angle, and what type of triangle is it based on its angles?

The third angle is 90 degrees, making it a right triangle.

Describe the properties of an equilateral triangle.

An equilateral triangle has three equal sides and three equal acute angles.

What is the relationship between equilateral triangles and acute triangles?

All equilateral triangles are acute triangles.

Classifying Triangles

6th GradeMath45 min

Learning Objective

I can classify triangles by their angles and sides.

Lesson Flow

Watch Video

8 min

Math Antics - Triangles

mathantics

Guided Notes

9 min

Key concepts students will learn:

•
Triangles are polygons that always have 3 sides and 3 angles.
•
Triangles can be classified by their sides (equilateral, isosceles, and scalene) and by their angles (right, acute, and obtuse).
•
The three angle measurements of any triangle, when combined, will always add up to 180 degrees.

Practice

14 min

9 questions • Multiple choice & Short answer

Exit Ticket

5 min

“Draw an example of an obtuse scalene triangle. Label the obtuse angle and indicate which sides, if any, are congruent.”

Teacher Guide

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Answer keys for all questions
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Classifying Triangles

Learning Objective

Lesson Flow

Watch Video

Guided Notes

Practice

Exit Ticket

Teacher Guide

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