Sample Quizzes For Preparation: Angles
O Level and IGCSE Mathematics – Chapter 4.6: Angles
1. What is the sum of angles at a point?
A. 180°
B. 360°
C. 90°
D. 270°
2. If two angles on a straight line are 130° and x°, what is the value of x?
A. 40°
B. 50°
C. 60°
D. 30°
3. What is the measure of a vertically opposite angle to 75°?
A. 105°
B. 85°
C. 75°
D. 65°
4. What is the angle sum in a triangle?
A. 270°
B. 360°
C. 180°
D. 90°
5. If two angles of a triangle are 60° and 85°, find the third angle.
A. 35°
B. 45°
C. 30°
D. 25°
6. The sum of the angles in a quadrilateral is:
A. 360°
B. 180°
C. 270°
D. 540°
7. In a quadrilateral, three angles are 80°, 95°, and 100°. What is the fourth angle?
A. 95°
B. 85°
C. 90°
D. 105°
8. Which of the following angles are equal when two parallel lines are cut by a transversal?
A. Interior and exterior angles
B. Alternate angles
C. Adjacent angles
D. Reflex angles
9. Corresponding angles in parallel lines are:
A. Equal
B. Supplementary
C. Complementary
D. Different
10. Co-interior angles in parallel lines sum to:
A. 360°
B. 90°
C. 180°
D. 270°
11. Alternate angles are also known as:
A. X-angles
B. Z-angles
C. U-angles
D. W-angles
12. If an alternate angle is 115°, its pair is:
A. 65°
B. 75°
C. 115°
D. 105°
13. If co-interior angle is 140°, its pair is:
A. 40°
B. 30°
C. 50°
D. 60°
14. The interior angle of a regular hexagon is:
A. 120°
B. 150°
C. 140°
D. 160°
15. What is the exterior angle of a regular pentagon?
A. 60°
B. 90°
C. 72°
D. 108°
16. Interior angle of a regular octagon:
A. 135°
B. 145°
C. 140°
D. 160°
17. Each exterior angle of a regular dodecagon (12 sides) is:
A. 25°
B. 30°
C. 45°
D. 60°
18. Sum of interior angles of a 9-sided polygon:
A. 1080°
B. 1260°
C. 1440°
D. 1170°
19. What is the sum of exterior angles of any polygon?
A. 180°
B. 270°
C. 360°
D. 540°
20. What is the three-letter notation for an angle with vertex at B?
A. AB
B. ACB
C. ABC
D. CB
21. Which angle is formed when two lines cross each other?
A. Reflex angle
B. Complementary angle
C. Vertically opposite angle
D. Co-interior angle
22. Which angle rule applies to this: “Angles on a straight line sum to 180°”?
A. Linear pair
B. Reflex rule
C. Opposite rule
D. Triangle rule
23. In a regular polygon, each interior angle = 150°. Find number of sides.
A. 10
B. 12
C. 8
D. 7
24. What is the sum of interior angles of a 7-sided polygon?
A. 900°
B. 1080°
C. 1260°
D. 180°
25. In triangle XYZ, angle X = 90°, angle Y = 45°. What is angle Z?
A. 55°
B. 35°
C. 45°
D. 90°
26. If one exterior angle of a polygon is 40°, how many sides does it have?
A. 9
B. 10
C. 8
D. 6
27. What is the missing angle in a triangle with two 70° angles?
A. 40°
B. 30°
C. 20°
D. 60°
28. Which of the following polygons is regular?
A. Rectangle
B. Square
C. Scalene Triangle
D. Trapezium
29. What is the interior angle of a regular decagon?
A. 144°
B. 140°
C. 120°
D. 150°
30. What is the exterior angle of a regular triangle?
A. 60°
B. 90°
C. 120°
D. 30°
Marking Key and Detailed Explanations – O Level and IGCSE Mathematics – Chapter 4.6: Angles
1. B. 360°
Explanation: The total angle around a point is always 360°.
2. A. 50°
Explanation: 180° − 130° = 50°, since angles on a straight line add up to 180°.
3. C. 75°
Explanation: Vertically opposite angles are equal.
4. C. 180°
Explanation: The sum of the interior angles of any triangle is 180°.
5. A. 35°
Explanation: 180° − (60° + 85°) = 35°.
6. A. 360°
Explanation: The interior angles of a quadrilateral always sum to 360°.
7. B. 85°
Explanation: 360° − (80° + 95° + 100°) = 85°.
8. B. Alternate angles
Explanation: Alternate angles are equal when lines are parallel.
9. A. Equal
Explanation: Corresponding angles are equal in parallel lines.
10. C. 180°
Explanation: Co-interior angles (U-shape) always sum to 180° in parallel lines.
11. B. Z-angles
Explanation: Alternate angles form a Z-shape.
12. C. 115°
Explanation: Alternate angles are equal.
13. A. 40°
Explanation: 180° − 140° = 40° for co-interior angles.
14. A. 120°
Explanation: (n−2)×180° / n = (6−2)×180 / 6 = 120°.
15. C. 72°
Explanation: Exterior angle = 360° / n = 360° / 5 = 72°.
16. A. 135°
Explanation: Interior angle = (8−2)×180 / 8 = 135°.
17. B. 30°
Explanation: 360° / 12 = 30° for exterior angle.
18. B. 1260°
Explanation: (9−2)×180 = 1260°.
19. C. 360°
Explanation: Sum of all exterior angles of any polygon is always 360°.
20. C. ABC
Explanation: The middle letter (B) represents the vertex of the angle.
21. C. Vertically opposite angle
Explanation: These are equal angles formed when two lines intersect.
22. A. Linear pair
Explanation: Linear angles are on a straight line and add to 180°.
23. B. 12
Explanation: Exterior angle = 180° − 150° = 30°, number of sides = 360° / 30° = 12.
24. A. 900°
Explanation: (7−2)×180 = 900°.
25. C. 45°
Explanation: 180° − (90° + 45°) = 45°.
26. B. 9
Explanation: 360° / 40° = 9.
27. D. 40°
Explanation: 180° − (70° + 70°) = 40°.
28. B. Square
Explanation: All sides and angles are equal in a square (regular polygon).
29. A. 144°
Explanation: (10−2)×180 / 10 = 144°.
30. A. 60°
Explanation: Exterior angle of an equilateral triangle = 360° / 3 = 120°, so interior = 60°.