The Exterior Angle Theorem
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Objective
I can use the exterior angle theorem to solve for missing angle measures in triangles.
Part 1 of 3
Warm-up video
Tutors · 2:43
We don't generate video — this one is by Tutors on YouTube. The practice questions and exit ticket below were drafted by AI for this objective, and every question is editable in the teacher guide.
Part 2 of 3
Practice
2 questions
In triangle PQR, the exterior angle at vertex R measures 125°. If the measure of angle P is 60°, find the measure of angle Q. Show your work.
An exterior angle of a triangle measures 105°. One of the non-adjacent interior angles measures 38°. Find the measure of the angle adjacent to the 105° exterior angle. Explain your reasoning.
Part 3 of 3
Exit ticket
Quick comprehension check
“In triangle ABC, the measure of exterior angle A is 130°. If the measure of angle B is 65°, find the measure of angle C. Show your work. In triangle XYZ, the measure of exterior angle X is 115°. If the measure of angle Y is 50°, find the measure of angle Z. Show your work. In triangle PQR, the measure of exterior angle P is 120°. If the measure of angle Q is 72°, find the measure of angle R. Show your work.”
Sample answer included in the free materials
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