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# RD Sharma Class 8 Solutions Chapter 21 Mensuration II - Volumes Surface Area of Cuboid and Cube Exercise 21.2 Last updated date: 29th Nov 2023
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## RD Sharma Class 8 Solutions Chapter 21 - Mensuration II - Volumes Surface Area Cuboid and A Cube (Ex 21.2) Exercise 21.2 - Free PDF

You can free PDF download of RD Sharma Class 8 Solutions Chapter 21 - Mensuration II - Volumes Surface Area Cuboid and a Cube Exercise 21.2 solved by expert Mathematics teachers on Vedantu. All Chapter 21 - Mensuration II - Volumes Surface Area Cuboid and  A Cube Ex 21.2 Questions with Solutions for RD Sharma Class 8 Maths is available on Vedantu to help you to revise the complete syllabus and score more marks.

RD Sharma solutions are recommended by many experts and toppers as it is in perfect sync with the CBSE curriculum. Experts at Vedantu have solved these exercises carefully and in the simplest ways so that students do not take much time to revise. Students are recommended to go through all the problems and practice them to achieve better scores. Vedantu also provides previous year question papers, solved exercises, reference materials, and textbooks in PDF format for free. You can download them or read Vedantu RD Sharma class 8 solutions.

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## FAQs on RD Sharma Class 8 Solutions Chapter 21 Mensuration II - Volumes Surface Area of Cuboid and Cube Exercise 21.2

1. What is a cuboid and how is it different from a rectangle?

Cuboid is a polygon represented in three-dimensional format on a plane surface. It has 6 surface areas similar to that of a rectangle. The rectangle is a quadrilateral with four sides, four angles and four vertices. The opposite sides of a rectangle are equal and all angles measure 90 degrees. A cuboid is a 3-D representation of a rectangle with length, breadth and perpendicular height. The rectangle is a 2D figure with only length and breadth. Gift boxes are the best example of a cuboid and a cot is the best example of a rectangle.

2. What is the formula to find the total surface area of a cuboid and cube?

Cuboid has 6 surface areas, 8 vertices and 12 edges. RD Sharma chapter 21 class 8 has many problems related to finding out the total surface area of a cuboid and mentions the formula for it:

• The total surface area of a cuboid is represented by T.S.A.

T.S.A. of cuboid = 2(lb + bh +lh)

where,

h = perpendicular height from the base

l = length of the cuboid

b = breadth of the cuboid

• Similarly, the total surface area of a cube is represented by T.S.A.

T.S.A of cube = 6a2

All the sides of a cube are equal as a cube is a 3D representation of a square

Here a = length of the side

3. What is the formula to find out the lateral surface area of a cuboid and its perimeter?

Lateral surface area is represented by L.S.A

L.S.A of cuboid = 2h(l + b)

l = length ; b= breadth; h = perpendicular height

Similarly, the perimeter of a cuboid is represented by P

P = 4(l+b+h)

l= length; b = breadth, h = perpendicular height

4. What is the formula to find out the volume of a cuboid and a cube?

Cuboid and cubes are polygons represented in three-dimensional format on a plane surface. RD Sharma chapter 21 class 8 has many problems related to finding out the volume of a cuboid and mentions the formula for the same:

• The volume of the cuboid is represented by V

V = l x b x h

l= length, b= breadth, h= height

• Similarly, the volume of a cube represented by V

V = a3

a= length of side .