Triangle Angle Quiz

Name:

Date:

📚 Part 1: Multiple Choice

I can... find missing interior and exterior angles of a triangle.

Success criteria: I can (1) use the fact that interior angles sum to 180°, (2) use that an exterior angle equals the sum of the two remote interior angles, and (3) show my work clearly.

1. What is the sum of the interior angles of any triangle?

90°

180°

360°

2. Two interior angles of a triangle measure 50° and 60°. What is the third interior angle?

70°

80°

90°

3. An exterior angle at one vertex measures 95°. Which interior angle is adjacent to that exterior angle?

85°

95°

105°

4. Check all sets that could be the three interior angles of a triangle:

30°, 60°, 90°

100°, 50°, 30°

120°, 40°, 20°

0°, 90°, 90°

✏️ Part 2: Short Answers & Reasoning

5. Find the missing interior angle: angles = 72° and 48°. Show your work.

6. At vertex A an exterior angle measures 130°. One remote interior angle (at B) is 40°. Find the other remote interior angle (at C). Show steps.

7. Explain in 1–2 sentences why an exterior angle of a triangle equals the sum of the two remote interior angles.

8. Draw a triangle that has interior angles 30° and 60°. Label the third interior angle and draw the exterior angle at the 60° vertex. What is the measure of that exterior angle?

Differentiation strategies: Provide a number line or angle tool for students who need visual support; allow calculation with a calculator for students who need focus on reasoning rather than arithmetic; offer one-on-one guided practice for students who struggle.

Extension activity (advanced learners): Given two angles in a triangle are in the ratio 2:3 and the exterior angle at the third vertex is 150°, find all three interior angles and explain your method.

Dyslexia-friendly reading options: Read questions aloud, provide printed copies with larger fonts, and allow colored overlays or high-contrast sheets. Shorten sentences and highlight key numbers (e.g., 180°, 130°).