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On January 25, 2024, 11:35 AM

Exercise 5.4 - Chapter 5 Understanding elementary shapes class 6 ncert solutions Maths - SaraNextGen [2024]


Question 1:

What is the measure of (i) a right angle? (ii) a straight angle?

Answer:

(i) The measure of a right angle is 90°.

(ii) The measure of a straight angle is 180°.

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.

Answer:

(a) True

The measure of an acute angle is less than 90°.

(b) False

The measure of an obtuse angle is greater than 90º but less than 180º.

(c) True

The measure of a reflex angle is greater than 180°.

(d) True

The measure of one complete revolution is 360º.

(e) True

Question 3:

Write down the measures of

(a) Some acute angles. (b) Some obtuse angles.

(Give at least two examples of each).

Answer:

(a) 45°, 70°

(b) 105°, 132°

Question 4:

Measure the angles given below using the Protractor and write down the measure.

https://img-nm.mnimgs.com/img/study_content/curr/1/6/1/5/1841/Exercise%20-%205_html_6a4e0ec3.jpg

Answer:

(a) 45º

(b) 120º

(c) 90º

(d) 60º, 90º, and 130º

Question 5:

Which angle has a large measure? First estimate and then measure.

Measure of angle A =

Measure of angle B =

https://img-nm.mnimgs.com/img/study_content/curr/1/6/1/5/1846/Exercise%20-%205_html_7248f557.jpg

Answer:

Measure of angle A = 40º

Measure of angle B = 68º

∠B has the greater measure than ∠A.

Question 6:

From these two angles which has larger measure? Estimate and then confirm by measuring them.

https://img-nm.mnimgs.com/img/study_content/curr/1/6/1/5/1850/Exercise%20-%205_html_m79dbd090.jpg

Answer:

The measures of these angles are 45º and 55º. Therefore, the angle shown in 2nd figure is greater.

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 _______.

Answer:

(a) Acute angle

(b) Obtuse angle (if the angle is less than 180º)

(c) Straight angle

(d) Acute angle

(e) Obtuse angle

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).

https://img-nm.mnimgs.com/img/study_content/curr/1/6/1/5/1859/Exercise%20-%205_html_2bf1abf.jpg

Answer:

The measures of the angles shown in the above figure are 40º, 130º, 65º, 135º respectively.

Question 9:

Find the angle measure between the hands of the clock in each figure:

https://img-nm.mnimgs.com/img/study_content/curr/1/6/1/5/1863/Exercise%20-%205_html_36d6fb1e.jpg

Answer:

(a) 90°

(b) 30°

(c) 180°

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?

https://img-nm.mnimgs.com/img/study_content/curr/1/6/1/5/1870/Exercise%20-%205_html_4bfca22f.jpg

Answer:

The measure of this angle will not change.

Question 11:

Measure and classify each angle:

https://img-nm.mnimgs.com/img/study_content/curr/1/6/1/5/1874/Exercise%20-%205_html_6a56ff99.jpg

Angle

Measure

Type

∠AOB

∠AOC

∠BOC

∠DOC

∠DOA

∠DOB

Answer:

Angle

Measure

Type

∠AOB

40º

Acute

∠AOC

125º

Obtuse

∠BOC

85º

Acute

∠DOC

95º

Obtuse

∠DOA

140º

Obtuse

∠DOB

180º

Straight

Also Read : Exercise-5.5-Chapter-5-Understanding-elementary-shapes-class-6-ncert-solutions-Maths

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