NCERT Class 6 Mathematics Fifth Chapter Understanding Elementary Shapes Exercise 5.4 Solutions
EXERCISE 5.4
(1) What is the measure of
(i) A right angle? = 90o
(ii) A straight angle? = 180o
(2) Say True or False:
(a) The measure of an acute angle < 90°. = T
(b) The measure of an obtuse angle < 90°. = F
(c) The measure of a reflex angle > 180°. = T
(d) The measure of one complete revolution = 360°. = T
(e) If m ∠A = 53° and m ∠B = 35°, then m ∠A > m ∠B. = T
(3) Write down the measures of
(a) Some acute angles. = 23° and 89°
(b) Some obtuse angles. = 91° and 179°
(4) Measure the angles given below using the Protractor and write down the measure.
(5) Which angle has a large measure? First estimate and then measure.
Measure of Angle A = 45°
Measure of Angle B = 60°
Angle B is greater than angle A.
(6) From these two angles which has larger measure? Estimate and then confirm by measuring them.
Ans: 2nd figure is larger than 1st figure.
(7) Fill in the blanks with acute, obtuse, right or straight:
(a) An angle whose measure is less than that of a right angle is acute.
(b) An angle whose measure is greater than that of a right angle is obtuse.
(c) An angle whose measure is the sum of the measures of two right angles is straight.
(d) When the sum of the measures of two angles is that of a right angle, then each one of them is acute.
(e) When the sum of the measures of two angles is that of a straight angle and if one of them is acute then the other should be an obtuse angle.
(8) Find the measure of the angle shown in each figure. (First estimate with your eyes and then find the actual measure with a protractor).
(9) Find the angle measure between the hands of the clock in each figure:
(10) Investigate in the given figure, the angle measures 30°.
Look at the same figure through a magnifying glass. Does the angle becomes larger? Does the size of the angle change?
(11) Measure and classify each angle:
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