# RS Aggarwal Class 8 Chapter 20 Solutions (Volume And Surface Area Of Solids)

RS Aggarwal Class 8 Maths Solutions for Chapter 20 ‘Volume and Surface Areas of Solids’ provide step-by-step answers to all the exercise questions of the chapter. Till now, you have learned how to find the surface area of two-dimensional shapes such as rectangle, trapezium, square and other polygons. In this chapter of RS Aggarwal Class 8 Maths Solutions, you will learn how to find the surface area of different three-dimensional solids such as a cube, cuboid, and cylinder. You will also learn how to find the volume of these solids.

Volume and Surface Area are two very important concepts that would not only help you gain good marks in Class 8 CBSE exams but also in higher classes. The exercise questions of the chapter introduce you to the formulas for surface area, lateral or curved surface area, and volume of three-dimensional solids that you must remember thoroughly. There are 3 exercises in the chapter and a total of 81 questions. This gives you an ample opportunity to practice the concepts and memorize the problem-solving procedures.

The RS Aggarwal Class 8 Maths Solutions for Chapter 20 ‘Volume and Surface Areas of Solids’ provided by our subject-matter experts are a perfect guide for you. These solutions will help you every time you face an issue in solving the exercises of this chapter. They will provide you with conceptual clarity and the right methodology to solve questions related to surface area and volume in the exams.

## Important Topics for RS Aggarwal Class 8 Maths Solutions Chapter 20: Volume and Surface Areas of Solids

**Surface Area of Solids **

A solid object is an object that has length, breadth, and height. A solid object has different faces. The surface area of a solid object is the area occupied by that solid object. This is also given by the surface area of each face of the solid object.

**Volume of Solids **

The volume of solids can be defined as the space occupied by that object. We can say that the number of unit cubes that can fill a solid object would determine its volume. However, there are specific formulae for finding the volume of different solids.

**Lateral Surface Area of Solids**

When the surface area of a solid object is calculated excluding the area of its base(s) then it is called a lateral surface area. It is also known as the curved surface area.

**Cube, Cuboid, and Cylinder **

**Cube: **It is a three-dimensional solid object made up of 6 squares. Each square forms a face of the cube. There are 8 vertices and 12 edges in a cube. All the interior angles of the cube are 90°.

**Cuboid:** It is a three-dimensional solid object made up of 6 rectangles. Each rectangle forms the face of the cuboid. There are 8 vertices and 12 edges in a cuboid. All the interior angles of the cuboid are 90°.

**Cylinder: **A cylinder has two circular flat ends or bases which are connected by a curved surface. It, therefore, has only 3 faces. If the cylinder has a circular base it is called a Right Circular Cylinder and if the cylinder has an Elliptical base then it is called an Elliptical Cylinder.

Area and Volume of Solids |
Cube
(Length: L) |
Cuboid
(Length: L Breadth: B Height: H) |
Cylinder
(Radius: R Height: H) |

Total Surface Area |
6(L^{2}) |
2(LB+BH+HL) | 2πR( R+H ) |

Lateral Surface Area |
4(L^{2}) |
2H(L+B) | 2πRH |

Volume |
L^{3} |
V = LxBxH | πR^{2}H |

### Exercise Discussion for RS Aggarwal Class 8 Maths Solutions Chapter 20: Volume and Surface Areas of Solids

- RS Aggarwal Class 8 Maths Solutions for Chapter 20 ‘Volume and Surface Areas of Solids’ contain a total of 80 questions for practice. All these questions are in accordance with the latest CBSE Class 8 Maths syllabus.
- Exercise 20A has 30 questions on finding the total surface area, lateral surface area, and volume of cubes and cuboids.
- This exercise includes different word problems that provide various real-life applications of cubes and cuboids such as matchbox, wooden planks, cisterns, swimming pool, etc.
- Exercise 20B has 21 questions finding the total surface area, lateral surface area, and volume of cylinders. Many application-based questions are also included in this exercise which you can relate to your daily life easily.
- Exercise 20C has 30 questions based on the total surface area, lateral surface area, and volume of cubes, cylinders, and cuboids. The questions in this exercise are not straightforward.
- For instance, in one question you are given the ratio of volumes of two cubes and you have to find the ratio of their surface areas.
- Similarly, there is another question where you are given the measure of the diagonal of a cube and you have to find its volume.
- This exercise also includes questions related to finding the volume of combinational solids. For instance, in one question it is given that 5 cubes are placed over each other and you have to calculate the volume of the resulting solid. This means you have to utilize your interpretational skills and imagination to picturise the question so that you can solve it correctly.

### Benefits of RS Aggarwal Class 8 Maths Solutions Chapter 20: Volume and Surface Areas of Solids by Instasolv

- Solving questions related to the total surface area, lateral surface area, and volume of cylinders, cubes, and cuboids is no more tricky for you as we have provided stepwise solutions for every problem.
- Exercise-wise RS Aggarwal Solutions for Class 8 Chapter 20 is a perfect way to resolve your queries regarding the chapter.
- You will be able to prepare for your Class 8 CBSE exams easily with the help of these solutions.