Missing Angles Worksheet

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📚 Part 1: Multiple Choice — Angle Relationships

Find the missing angle using angles on a straight line, angles at a point, or vertically opposite angles.

1. On a straight line, one angle is 120°. What is the adjacent angle?

60°

120°

90°

30°

2. At a point, two of the angles are 80° and 140°. What is the third angle?

100°

140°

120°

160°

3. Two straight lines cross. One angle measures 55°. What is the vertically opposite angle?

55°

125°

45°

180°

4. On a straight line, the angles are 2x° and 40°. What is x?

5. Two lines intersect. Angle 1 = 3x + 10° and the vertically opposite angle 2 = 5x − 20°. Find x and the angle measure.

6. At a point, three angles are 120°, 2x° and (x + 30)°. Find x.

7. On a straight line the adjacent angles are (x + 20)° and (2x + 10)°. Find x and give both angle measures.

8. Two lines cross. One angle is 4x − 10° and its vertically opposite angle is 70°. Find x and confirm the angle value.