# RS Aggarwal Class 8 Maths Chapter 20 Ex 20.1 Solutions 2022 | Download Free PDF

RS Aggarwal Class 8 Maths Chapter 20 Ex 20.1 Solutions: In this exercise, the students will learn the calculation of volume, total surface area, and missing height, breadth, and width of a cube and cuboid. These solutions provide a detailed answer to all the questions available in the RS Aggarwal textbook. Cube & cuboid are three-dimensional shapes that comprise 6 faces, 8 vertices, and 12 edges.

The main difference between them is a cube has all its sides equal whereas the length, width, and height of a cuboid are different. The shape of the cube & cuboid looks almost similar but has different properties. These solutions help the students by providing them the detailed answers with examples after each question. These solutions also assist the students to have a proficient studying pattern with which they can secure higher marks in the Maths exam.

## Download RS Aggarwal Class 8 Maths Chapter 20 Ex 20.1 Solutions

RS Aggarwal Class 8 Maths Chapter 20 Ex 20.1 Solutions

## Important Definition for RS Aggarwal Class 8 Maths Chapter 20 Ex 20.1 Solutions

• Cube

It is a 3D figure that is defined as the XYZ plane. It has 6 faces, 8 vertices, and 12 edges. All the faces of the cube are in square shape and have equal dimensions.

• Cuboid:

It is also a polyhedron having 6 faces, 8 vertices, and 12 edges. The faces of the cuboid are parallel. But not all the faces of a cuboid are equal in dimensions.

• Formulas of Cube and Cuboid

Cube

Total Surface Area = 6(side)2

Lateral Surface Area = 4 (Side)2

Volume of cube = (Side)3

Diagonal of a cube = √3l

Perimeter of cube = 12 x side

Cuboid

Total Surface area = 2 (Length x Breadth + breadth x height + Length x height)

Lateral Surface area = 2 height (length + breadth)

Volume of the cuboid = (length × breadth × height)

Diagonal of the cuboid = √( l2 + b2 + h2)

Perimeter of cuboid = 4 (length + breadth + height)

• Surface Area of Cube and Cuboid

The surface area of a cuboid is equal to the sum of the areas of its 6 rectangular faces.

Assume a cuboid having the length to be ‘l’ cm, breadth be ‘b’ cm & height be ‘h’ cm.

Area of face EFGH = Area of Face ABCD = (l × b) cm2

Area of face BFGC = Area of face AEHD = (b × h) cm2

Area of face DHGC = Area of face ABFE = (l × h) cm2

Total surface area of a cuboid = Sum of the areas of all its 6 rectangular faces

Total Surface Area of Cuboid= 2(lb + bh + lh)

• Volume of the Cube and Cuboid

Volume of Cuboid: It is equal to the product of the area of one surface and height.

Volume of the cuboid = (length × breadth × height) cubic units

Volume of the Cube: It is equal to the product of the area of the cube and height.

Volume of the cube = l2 × h but l = h

Thus, Volume of the cube = l2 × l

Volume of the cube = l3

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