Chapter 9: Lines and Angles - Mock Test
Instructions
- •This test has 20 questions covering all topics from Chapter 9
- •Questions are arranged as per CBSE paper pattern
- •Section A: 8 questions × 1 mark = 8 marks
- •Section B: 8 questions × 2 marks = 16 marks
- •Section C: 4 questions × 4 marks = 16 marks
- •No negative marking
Mock Test Questions
Section A: 1 Mark Questions (8 × 1 = 8 marks)
1. What is the complement of 37°?
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Answer: 90° - 37° = 53°
2. What is the supplement of 120°?
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Answer: 180° - 120° = 60°
3. A ray has _____ endpoints.
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Answer: One endpoint
4. Classify the angle 150°.
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Answer: Obtuse angle
5. Write the notation for 'line AB is parallel to line CD'.
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Answer: AB || CD
6. What type of angle is 90°?
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Answer: Right angle
7. Name two vertically opposite angles when two lines intersect.
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Answer: ∠1 and ∠3 are vertically opposite (or ∠2 and ∠4)
8. How many degrees in a straight angle?
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Answer: 180°
Section B: 2 Mark Questions (8 × 2 = 16 marks)
9. Two angles are complementary. If one is 42°, find the other.
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Answer: Other angle = 90° - 42° = 48°
10. Two angles form a linear pair. If one is 65°, find the other.
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Answer: Linear pair sums to 180°. Other angle = 180° - 65° = 115°
11. When two lines intersect, one angle is 75°. What are the four angles formed?
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Answer: The four angles are 75°, 105°, 75°, 105° (vertically opposite angles are equal)
12. Define perpendicular lines and give a real-life example.
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Answer: Lines intersecting at 90°. Example: Floor and walls of a room
13. In a linear pair, one angle is three times the other. Find both angles.
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Answer: Let angles be x and 3x. x + 3x = 180°; 4x = 180°; x = 45°. Angles are 45° and 135°
14. Classify the following angles: 45°, 100°, 180°, 270°
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Answer: 45° = Acute, 100° = Obtuse, 180° = Straight, 270° = Reflex
15. What is the sum of angles formed on a straight line?
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Answer: Sum of angles on a straight line = 180°
16. Two lines are parallel. What can you say about the distance between them?
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Answer: The distance between parallel lines is constant (always the same)
Section C: 4 Mark Questions (4 × 4 = 16 marks)
17. Three angles are formed at a point. They are in ratio 1:2:3. Find all three angles.
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Answer: Let angles = x, 2x, 3x Sum = 360° (angles around a point) x + 2x + 3x = 360° 6x = 360° x = 60° Angles are: 60°, 120°, 180°
18. Two adjacent angles form a linear pair. If their ratio is 2:7, find the angles.
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Answer: Let angles = 2k and 7k Linear pair: 2k + 7k = 180° 9k = 180° k = 20° Angles are: 40° and 140°
19. When two lines intersect, vertically opposite angles are (2x + 15)° and (3x - 5)°. Find x and the angle measures.
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Answer: Vertically opposite angles are equal: 2x + 15 = 3x - 5 15 + 5 = 3x - 2x 20 = x Angle = 2(20) + 15 = 55° Both vertically opposite angles = 55° each
20. Draw two perpendicular lines AB and CD intersecting at O. Mark all four angles and state their measures.
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Answer: Two perpendicular lines intersect at O at 90° All four angles = 90° each Mark with small square symbols at vertex O ∠AOC = ∠COB = ∠BOD = ∠DOA = 90°
Marking Scheme & Evaluation
Section A (1 Mark)
1 mark for correct answer. No partial marking.
Section B (2 Marks)
- • Correct answer with working: 2 marks
- • Correct method but minor error: 1 mark
- • Wrong answer: 0 marks
Section C (4 Marks)
- • Correct with all steps: 4 marks
- • Correct approach with minor errors: 3 marks
- • Partially correct (≥50%): 2 marks
- • Some working shown: 1 mark
- • No attempt: 0 marks
Performance Analysis
36-40 marks: Excellent! You have mastered the chapter.
30-35 marks: Very Good! Strong understanding of concepts.
24-29 marks: Good! Revise weaker areas and practice more.
18-23 marks: Average. Focus on difficult concepts.
Below 18 marks: Need improvement. Review fundamentals.
Exam Preparation Tips
- ✓Always draw diagrams for angle problems - visual representation helps
- ✓Remember: Complementary = 90°, Supplementary = 180°
- ✓Vertically opposite angles are always equal - use this property
- ✓When writing angle notation, middle letter is the vertex
- ✓Practice identifying parallel and perpendicular lines in real objects