 NCERT Solutions for Class 6 Maths Chapter 5 Understanding Elementary Shapes Ex 5.1
 NCERT Solutions for Class 6 Maths Chapter 5 Understanding Elementary Shapes Ex 5.2
 NCERT Solutions for Class 6 Maths Chapter 5 Understanding Elementary Shapes Ex 5.3
 NCERT Solutions for Class 6 Maths Chapter 5 Understanding Elementary Shapes Ex 5.4
 NCERT Solutions for Class 6 Maths Chapter 5 Understanding Elementary Shapes Ex 5.5
 NCERT Solutions for Class 6 Maths Chapter 5 Understanding Elementary Shapes Ex 5.6
 NCERT Solutions for Class 6 Maths Chapter 5 Understanding Elementary Shapes Ex 5.7
 NCERT Solutions for Class 6 Maths Chapter 5 Understanding Elementary Shapes Ex 5.8
NCERT Solutions for Class 6 Maths Chapter 5 Understanding Elementary Shapes Ex 5.4 (Rationalised Contents)
Ex 5.4 Class 6 Maths Question 1.
What is the measure of (i) a right angle (ii) a straight angle?Solution:
(i) The measure
of a right angle is 90°.
(ii) The measure of a straight angle is 180°.
Ex 5.4 Class 6 Maths Question 2.
Say True or False:(a) The measure of an acute angle < 90°.
(b) The measure of an obtuse angle < 90°.
(c) The measure of a reflex angle > 180°.
(d) The measure of one complete revolution = 360°.
(e) If m∠A = 53° and m∠B = 35°, then m∠A > m∠B.
Solution:
(a) True
(b) False
(c) True
(d) True
(e) True
Ex 5.4 Class 6 Maths Question 3.
Write down the measures of(a) some acute angles.
(b) some obtuse angles.
Solution:
(a) 35°, 48°
and 84° are examples of acute angles.
(b) 96°, 107° and 145° are examples of obtuse angles.
Ex 5.4 Class 6 Maths Question 4.
Measure the angles given below using the protractor and write down the measure.Solution:
(a) 45°
(b) 125°
(c) 90°
(d) ∠1 = 60°, ∠2 = 85°, ∠3 = 125°
Ex 5.4 Class 6 Maths Question 5.
Which angle has a large measure? First estimate and then measure.Measure of Angle A =
Measure of Angle B =
Solution:
The angle B has the larger measure.
Measure of
Angle A = 45°
Measure of Angle B = 60°
Ex 5.4 Class 6 Maths Question 6.
From these two angles which has large measure? Estimate and then confirm by measuring them.Solution:
The opening
of angle (b) is greater than the opening of angle (a).
∴ Measure of
angle (b) is larger.
Measure of angle (a) = 40°
and the measure of angle (b) = 60°
Ex 5.4 Class 6 Maths Question 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 ……… .
(b) An angle whose measure is greater than that of a right angle is ……… .
(c) An angle whose measure is the sum of the measures of two right angles is ……… .
(d) When the sum of the measures of two angles is that of a right angle, then each one of them is ……… .
(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 ……… .
Solution:
(a) acute
(b) obtuse
(c) straight
(d) acute
(e) obtuse
Ex 5.4 Class 6 Maths Question 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).Solution:
(a) Measure of the angle = 40°
(b) Measure of the angle = 130°
(c) Measure of the angle = 65°
(d) Measure of the angle = 135°
Ex 5.4 Class 6 Maths Question 9.
Find the angle measure between the hands of the clock in each figure:Solution:
(i) The angle measure between the hour hand and minute hand of a clock at
9.00 a.m. is 90°.
(ii) The angle measure between the hour hand and minute hand of a clock at 1.00
p.m. is 30°.
(iii) The angle measure between the hour hand and minute hand of a clock at
6.00 p.m. is 180°.
Ex 5.4 Class 6 Maths Question 10.
Investigate: In the given figure, the angle measures 30°. Look at the same figure through a magnifying glass. Does the angle become larger? Does the size of the angle change?Solution:
When we look at the same figure through a magnifying glass, the size of the figure will become larger but the measure of the angle will remain the same. Thus, the size of the angle will not change. Do this activity yourself to verify this.
Ex 5.4 Class 6 Maths Question 11.
Measure and classify each angle:
Angle 
Measure 
Type 
∠AOB 


∠AOC 


∠BOC 


∠DOC 


∠DOA 


∠DOB 


Solution:
Angle 
Measure 
Type 
∠AOB 
40° 
Acute angle 
∠AOC 
125° 
Obtuse angle 
∠BOC 
85° 
Acute angle 
∠DOC 
95° 
Obtuse angle 
∠DOA 
140° 
Obtuse angle 
∠DOB 
180° 
Straight angle 
Related Links:
NCERT Solutions for Maths Class 7
NCERT Solutions for Maths Class 8
NCERT Solutions for Maths Class 9
NCERT Solutions for Maths Class 10