Page 44 - Mathematics Class - IX

Viva-Voce

1. In a linear pair, if two adjacent angles are equal, what is the measure of each angle?
Ans. 90°
2. What is the measure of a straight angle?
Ans. 180°

3. Define reflex angle.
Ans. An angle which is greater than 180° but less than 360° is called a reflex angle. For example 280°.
4. Two lines intersect at a point. If measure of one angle is 110°, find the measures of other angles.
Ans. The other angles are 70°, 110°, 70°.

5. Two adjacent angles always have a sum of 180° in a linear pair. Yes or No?
Ans. Yes.
6. How many perpendiculars can be drawn to a line segment from a point lying outside it?
Ans. Only one.

MCQs

1. If the difference between two supplementary angles is 40°, then the angles are
a) 210°, 150° b) 70°, 110° c) 65°, 125° d) None of these

2. The complementary angle of 75° is

a) 25° b) 105° c) 5° d) 15°
3. In the given figure, AOB is a straight line. Find the value of a.

a) 75°

b) 60°

c) 37°
d) 45°

4. If two adjacent angles on a straight line are in the ratio 3 : 2, the measure of each angle is
a) 108°, 72° b) 100°, 80° c) 160°, 20° d) 140°, 40°

5. The supplementary angle of 145° is

a) 45° b) 0° c) 35° d) 25°

Answers: 1. b) 70°, 110° 2. d) 15° 3. c) 37°

4. a) 108°, 72° 5. c) 35°

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