Page 59 - Ganit Kaushal
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(c) The measure of a reflex angle > 180°.
(d) The hour hand of a clock rotates at the rate of 30° per hour.
(e) The minute hand of a clock rotates at the rate of 6° per minute.
(f) The magnitude of an angle does not depend on its arms.
(g) Twice of an acute angle is always an obtuse angle.
(h) Half of a reflex angle is always obtuse.
(i) Half of an obtuse angle is always obtuse.
(j) To make a unit to measure an angle, mathematicians divided one full circle into 180 equal parts.
Subjective/Competency Based Questions
13. Find the measure of the angle between the hands of the clock in each figure:
(a) (b) (c)
14. Write the measure of the smaller angle formed by the hour and the minute hands of a clock at
7 o’clock. Also, write the measure of the other angle and state what type of angles these are.
15. Find the acute angle between the hands of a clock at 3:30 pm.
16. What is the disadvantage of comparing angles by mere observation?
17. What are the different methods to compare any two angles?
18. In the given figure:
(a) Name:
(i) The parallel lines
(ii) All pairs of intersecting lines
(iii) Concurrent lines
(b) State whether the following statements are true or false:
(i) Points A, B, and D are collinear.
(ii) Lines AB and ED intersect at C.
19. Associated with the adjoining figure, write:
(a) All pairs of parallel lines
(b) All pairs of intersecting lines
(c) Lines whose point of intersection is E
(d) Collinear points
20. Find the number of degrees turned through by the hour hand of a clock when it goes from:
(a) 4 to 10 (b) 9 to 12 (c) 1 to 7
Lines and Angles 57
