Triangle Angles Add Up to 180
Grade 4•45 minutes•5.MG.3 The student will classify and measure angles and triangles, and solve problems, including those in context.
Learning Objective
I can prove that the angles inside a triangle add up to 180° using models and find a missing angle in a triangle.
Practice Questions
This lesson includes 7 practice questions to reinforce learning.
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1. Explain in your own words why the angles inside a triangle always add up to 180°.
2. Draw a triangle and label its angles as A, B, and C. If angle A is 60° and angle B is 80°, what is the measure of angle C?
3. Imagine you have a triangle where two of the angles are the same size, and the third angle is 90°. What are the measures of the two equal angles?
...and 4 more questions
Educational Video
Proof: Sum of measures of angles in a triangle are 180 | Geometry | Khan Academy
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