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Calculating Unknown Angles
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Calculating Unknown Angles
📐 Part 1: Basic Angle Facts
1. What do angles on a straight line add up to?
90°
180°
270°
360°
2. What do angles around a point add up to?
90°
180°
270°
360°
3. If one angle on a straight line is 65°, what is the other angle?
Answer: ___________
4. Two angles around a point are 120° and 85°. What is the third angle?
🔺 Part 2: Angles in Triangles and Quadrilaterals
5. What do the interior angles of a triangle add up to?
Answer: ___________
6. In a triangle, two angles are 45° and 60°. Find the third angle.
7. What do the interior angles of a quadrilateral add up to?
180°
270°
360°
540°
8. In a quadrilateral, three angles are 95°, 85°, and 90°. Find the fourth angle.
🧮 Part 3: Algebra with Angles
9. Two angles on a straight line are x° and (x + 40)°. Find the value of x.
10. In a triangle, the angles are 2x°, 3x°, and 4x°. Find the value of x.
11. Extension Challenge: In a quadrilateral, the angles are x°, (x + 20)°, (2x - 10)°, and (x + 30)°. Find the value of x and all four angles.
12. Explain in your own words how you can use algebra to solve angle problems:
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