CBSE Class 9 Lines and Angles MCQs – Basic Angle Relationships & Linear Pairs
CBSE Class 9 Lines and Angles MCQs – Basic Angle Relationships & Linear Pairs
Class: 9 | Subject: Mathematics | Chapter: 6 – Lines and Angles
Board: CBSE | Based on Latest NCERT Curriculum
Board: CBSE | Based on Latest NCERT Curriculum
These MCQs are strictly designed as per the CBSE Class 9 Mathematics syllabus and NCERT textbook guidelines. Ideal for school exams and board preparation.
1. If two angles form a linear pair, their sum is:
Answer: B. 180°
A linear pair consists of two adjacent angles forming a straight line, so their sum is 180°.
A linear pair consists of two adjacent angles forming a straight line, so their sum is 180°.
2. Vertically opposite angles are always:
Answer: C. Equal
When two lines intersect, vertically opposite angles are equal.
When two lines intersect, vertically opposite angles are equal.
3. Two angles whose sum is 90° are called:
Answer: B.
Complementary angles add up to 90°.
Complementary angles add up to 90°.
4. Two angles whose sum is 180° are:
Answer: C.
Supplementary angles add to 180°.
Supplementary angles add to 180°.
5. If one angle of a linear pair is 120°, the other is:
Answer: A.
Sum is 180° → 180−120=60°.
Sum is 180° → 180−120=60°.
6. If two lines intersect, number of pairs of vertically opposite angles formed is:
Answer: B.
Four angles are formed giving two vertical pairs.
Four angles are formed giving two vertical pairs.
7. Adjacent angles share:
Answer: C.
Adjacent angles share a vertex and a common arm.
Adjacent angles share a vertex and a common arm.
8. If one vertically opposite angle is 75°, the other is:
Answer: A.
Vertically opposite angles are equal.
Vertically opposite angles are equal.
9. A straight angle measures:
Answer: B.
Straight angle forms a straight line.
Straight angle forms a straight line.
10. If two angles are complementary and one is 30°, the other is:
Answer: A.
90−30=60°.
90−30=60°.
11. If two lines are parallel and a transversal intersects them, alternate interior angles are:
Answer: B.
Alternate interior angles are equal for parallel lines.
Alternate interior angles are equal for parallel lines.
12. Corresponding angles are equal when lines are:
Answer: B.
Parallel lines give equal corresponding angles.
Parallel lines give equal corresponding angles.
13. If two angles form a linear pair, they are:
Answer: A.
Linear pair are adjacent and sum to 180°.
Linear pair are adjacent and sum to 180°.
14. An angle greater than 90° but less than 180° is:
Answer: C.
Obtuse angle lies between 90° and 180°.
Obtuse angle lies between 90° and 180°.
15. Reflex angle measures:
Answer: C.
Reflex angles are greater than 180°.
Reflex angles are greater than 180°.
16. If two angles are supplementary and one is 100°, the other is:
Answer: A.
180−100=80°.
180−100=80°.
17. When two lines intersect, sum of adjacent angles is:
Answer: B.
Adjacent angles form linear pair.
Adjacent angles form linear pair.
18. If alternate interior angles are equal, lines are:
Answer: B.
This is a test for parallel lines.
This is a test for parallel lines.
19. The sum of angles around a point is:
Answer: B.
Angles around a point add up to 360°.
Angles around a point add up to 360°.
20. A right angle measures:
Answer: B.
A right angle measures exactly 90°.
A right angle measures exactly 90°.
