The angle equal to its complement is 45° and the angle equal to its supplement is 90°, so this Class 9 sheet opens by matching the two angle pairs. The key lists 60°, 72°, 40° and 52.5° as its other angle answers.
Key Takeaways
The angle equal to its complement is 45° (Q1).
The angle equal to its supplement is 90° (Q2).
Q3 records 60° among the answers.
Section A: Multiple Choice Questions (1 Mark Each)
Choose the correct option for each question.
1.The angle which is equal to its complement is
(a) 30°(b) 45°(c) 60°(d) 90°
2.The angle which is equal to its supplement is
(a) 90°(b) 45°(c) 60°(d) 120°
3.Two complementary angles are in the ratio 1 : 2. The larger angle is
(a) 30°(b) 45°(c) 60°(d) 120°
4.Two angles of a linear pair are in the ratio 2 : 3. The smaller angle is
(a) 36°(b) 54°(c) 72°(d) 108°
5.An angle is 10° less than its complement. The angle is
(a) 40°(b) 45°(c) 50°(d) 80°
6.An exterior angle of a triangle is 105° and its two interior opposite angles are equal. Each interior opposite angle is
(a) 52.5°(b) 45°(c) 55°(d) 50°
Section B: Short Answer Type Questions (2 Marks Each)
Show all steps clearly.
7.Two angles of a linear pair measure (2x)° and (3x)°. Find the value of x.
8.Write the complement of 35°.
9.Write the supplement of 115°.
10.In ΔABC, if ∠A = 65° and ∠B = 75°, find ∠C.
11.State the angle-sum property of a triangle.
12.If two parallel lines are cut by a transversal, what is the relation between the corresponding angles?
13.Find the value of x if x° and (x + 20)° form a linear pair.
14.An angle is 30° more than its supplement. Find the angle.
Section C: Numericals & Word Problems (3 Marks Each)
Apply the concepts to solve the problems. Show all working.
15.The angles of a triangle are in the ratio 2 : 3 : 5. Find the measure of each angle.
16.Two supplementary angles differ by 40°. Find the angles.
17.In ΔABC, the exterior angle at C is 120° and the interior opposite angles ∠A and ∠B are equal. Find ∠A.
18.A transversal intersects two parallel lines such that the alternate interior angles are (3x + 10)° and (2x + 30)°. Find the value of x.
19.The ratio of the complement of an angle to its supplement is 1 : 4. Find the angle.
20.In a right triangle, one acute angle is three times the other acute angle. Find the two acute angles.
Answer Key
1. b) 45°
2. a) 90°
3. c) 60°
4. c) 72°
5. a) 40°
6. a) 52.5°
7. Refer to solution guide.
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19. Refer to solution guide.
20. Refer to solution guide.
End of Worksheet
People Also Ask
Which angle equals its complement?
45°, option (b) in this worksheet (Q1).
Which angle equals its supplement?
90°, option (a) in this worksheet (Q2).
What is the third angle of a triangle with two 60° angles?
60°, option (c) in this worksheet (Q3).
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