# RBSE Solutions for Class 8 Maths Chapter 15 Surface Area and Volume In Text Exercise

RBSE Solutions for Class 8 Maths Chapter 15 Surface Area and Volume In Text Exercise is part of RBSE Solutions for Class 8 Maths. Here we have given Rajasthan Board RBSE Class 8 Maths Chapter 15 Surface Area and Volume In Text Exercise.

 Board RBSE Textbook SIERT, Rajasthan Class Class 8 Subject Maths Chapter Chapter 15 Chapter Name Surface Area and Volume Exercise In Text Exercise Number of Questions 9 Category RBSE Solutions

## Rajasthan Board RBSE Class 8 Maths Chapter 15 Surface Area and Volume In Text Exercise

Page No: 180

Question 1.
If a cuboid is formed by sticking three cubes of side x then what will be the dimensions of cuboid.

Solution:
Position I
Length = 3x
Height = x

Position II
Length = x
Height = 3x

Page No: 181

Question 2.
Find out surface area of a cube having side 3 cm. What will be the(RBSESolutions.com)surface area of 5 such cubes?
Solution:
Surface area of cube of side 3 cm.
= 6 a²
= 6(3)²
= 54 cm.²
Surface area of 5 cubes
= 54 x 5
= 270 cm.²

Question 3.
What will be the total surface area of 5 cubes having side 3 cm.? If they are stocked one after one, then how much surface area will be decreased?
Solution:
Total surface area of 5 cubes each of 3 side = 270 cm² (See the solution of question 1)
If 5 cubes are joined one(RBSESolutions.com)after one, then it becomes a cuboid whose length (l)
= 3 cm. + 3 cm. + 3 cm. + 3 cm. + 3 cm.
= 15 cm.
Height (h) = 3 cm.
∴ Surface Area= 2 (lb + bh + hl).
= 2 (15 x 3 + 3 x 3 + 3 x 15)
= 2 (45 + 9 + 45)
= 198 cm²
∴ Hence, surface area will be reduced and the difference = 270 cm.² – 198 cm.²
= 72 cm.²

Question 4.
Find out lateral surface area of the given cuboid.

Solution:
Here, l = 10 cm.
b = 4 cm.
h = 4 cm.
∴Lateral surface area of cuboid
= 2 (l + b) h
= 2 (10 + 4) 4
= 112 cm.²

Page No: 182

Question 5.
Determine total surface area(RBSESolutions.com)of following cylinders

Solution:
(i) Here, r = $$\frac { 7 }{ 2 }$$
h = 10 cm
∴ Total surface are of cylinder
= 2πr (h + r)

Page No: 186

Question 6.
By arranging cubes of unit length And volume of cuboid so obtained

Solution:

Page No: 187

Question 7.
Find volume of cuboid(RBSESolutions.com)on basis of given measures –

Solution:
(i) Here, l = 8 cm.
b = 3 cm.
h = 2 cm.
∴ Volume of cuboid
= l x b x h
= 8 x 3 x 2
= 48 cm.³
(ii) Here, l = 1 cm.
b = 1 cm.
h = 7 cm.
∴ Volume of cuboid
= l x b x h
= 1 x 1 x 7
= 7 cm³

Page No: 187

Question 8.

Solution

Page No: 188

Question 9.
Determine volume(RBSESolutions.com)of the cube having side
(i) 1.5 cm
(ii) 4 m
Solution:
(i) 1.5 cm
Here, a = 1.5 cm
∴ Volume of cube = a³
= (1.5)³
= 1.5 x 1.5 x 1.5
= 3.375 cm³
(ii) 4 cm
Here, a = 4 cm
∴ Volume of cube = a³
= (4)³
= 4 x 4 x 4
= 64 cm³

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