NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3

NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 are part of NCERT Solutions for Class 8 Maths. Here we have given NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3.

BoardCBSE
TextbookNCERT
ClassClass 8
SubjectMaths
ChapterChapter 11
Chapter NameMensuration
ExerciseEx 11.3
Number of Questions Solved10
CategoryNCERT Solutions

NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3

Question 1.
There are two cuboidal boxes as shown in the adjoining figure. Which box requires the lesser amount of material to make?
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 1
Solution.
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 2

Question 2.
A suitcase with measures 80 cm x 48 cm x 24 cm is to be covered with a tarpau¬lin cloth. How many meters of tarpaulin of width 96 cm is required to cover 100 such suitcases?
Solution.
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 3

Question 3.
Find the side of a cube whose surface area is 600 \({ cm }^{ 2 }\).
Solution.
Let the side of the cube be a cm.
Then, Total surface area of the cube = 6\({ a }^{ 2 }\)
According to the question,
6\({ a }^{ 2 }\)= 600
⇒ \({ a }^{ 2 }\) = \(\frac { 600 }{ 6 } \)
⇒ \({ a }^{ 2 }\) = 100
⇒ a = \(\sqrt { 100 } \)
⇒ a = 10 cm
Hence, the side of the cube is 10 cm.

Question 4.
Rukhsar painted the outside of the cabinet of measure 1 m x 2 m x 1.5 m. How much surface area did she cover if she painted all except the bottom of the cabinet?
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 4
Solution.
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 5

Question 5.
Daniel is painting the walls and ceiling of a cuboidal hall with length, breadth, and height of 15 m, 10 m and 7 m respectively. From each can of paint 100 \({ m }^{ 2 }\) of area is painted.
How many cans of paint will she need to paint the room?
Solution.
l = 15 m
b = 10 m
h = 7 m
Surface area to be painted
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 6
Hence, she will need 5 cans of paint to paint the room.

Question 6.
Describe how the two figures at the right are alike and how they are different. Which box has a larger lateral surface area?
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 7
Solution.
Similarity → Both have the same heights.
Difference → One is a cylinder, the other is a cube;
The cylinder is a solid obtained by revolving a rectangular area about its one side whereas a cube is a solid enclosed by six square faces; a cylinder has two circular faces whereas a cube has six square faces.
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 8

Question 7.
A closed cylindrical tank of radius 7 m and height 3 m is made from a sheet of metal. How many sheets of metal is required?
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 9
Solution.
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 10

Question 8.
The lateral surface area of a hollow cylinder is 4224 \({ cm }^{ 2 }\). It is cut along its height and formed a rectangular sheet of width 33 cm. Find the perimeter of rectangular sheet?
Solution.
Lateral surface area of the hollow cylinder = 4224 \({ cm }^{ 2 }\)
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 11

Question 9.
A road roller takes 750 complete revolutions to move once over to level a road. Find the area of the road if the diameter of a road roller is 84 cm and length is 1 m.
Solution.
Diameter of the road roller = 84 cm
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 12
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 13

Question 10.
A company packages its milk powder in the cylindrical container whose base has a diameter of 14 cm and height 20 cm. The company places a label around the surface of the container (as shown in the figure). If the label is placed 2 cm from top and bottom, what is the area of the label?
Solution.
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 14
NCERT Solutions for Class 8 Maths Chapter 11 Mensuration Ex 11.3 15

 

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