# RS Aggarwal Class 8 Chapter 19 Solutions (Three Dimensional Figures)

RS Aggarwal Class 8 Maths Solutions for Chapter 19 ‘Three-Dimensional Figures’ will help you understand the various properties of three-dimensional shapes. Till now, you have studied various two-dimensional figures such as rectangle, square, triangle, circle, pentagon, hexagon, etc. In this chapter of RS Aggarwal Class 8 Maths Solutions, you will study what are the various three-dimensional shapes and how they are formed.

This chapter is an introduction to three-dimensional geometry to you. So, you must follow all the concepts explained in the chapter carefully as this chapter is the foundation for many chapters of Class 9. There are only 9 questions in this chapter and 2 exercises but all these questions are very important from the exam perspective. These questions are based on properties of different three-dimensional shapes such as a cube, cuboid, pyramid, tetrahedron, and prism.

Instasolv has provided you with complete solutions to the exercises of Chapter 19 of RS Aggarwal Class 8 Maths book. You must refer to the important topics discussed below and get a complete overview of the chapter before solving the exercises. The exercise solutions are prepared by best geometry subject matter experts who are well-versed in the Class 8 Maths curriculum as given in the RS Aggarwal book and by CBSE.

## Important Topics for RS Aggarwal Class 8 Maths Solutions Chapter 19: Three-Dimensional Figures

**Three-Dimensional Figures **

A three-dimensional shape has three attributes – length, breadth, and height. It is unlike two-dimensional shapes that have only two attributes – length and breadth. Due to the presence of height, the three-dimensional shapes have different faces. For example, a dice is a three-dimensional object with 6 faces. Here is a summary of some three-dimensional objects.

**Types of Three-Dimensional Figures **

**Cube **

Number of faces: 6

Number of edges: 12

Number of vertices: 8

Other properties: all sides of a cube are equal to each other

**Cuboid**

Number of faces: 6

Number of edges: 12

Number of vertices: 8

Other properties: it is made up of 6 rectangles and two squares

**Pyramid**

Number of faces: 6

Number of edges: 8

Number of vertices: 5

Other properties: it is made up of three triangles that meet at one point on the top and a square-shaped base. A triangular pyramid is also known as a tetrahedron.

**Cylinder **

Number of faces: 3

Number of edges: 2

Number of vertices: 0

Other properties: it is made up of two circles and a curved surface that connects these two circles.

**Cone**

Number of faces: 2

Number of edges: 1

Number of vertices: 1

Other properties: it is made up of one circular base and a curved surface above that base.

**Sphere**

Number of faces: 1

Number of edges: 0

Number of vertices: 0

Other properties: it consists of one curved surface.

**Types of Pyramids**

- The base of a pyramid can be any regular or irregular polygon. If the base is a regular polygon then it is called a regular pyramid and if the base is an irregular polygon then it is called an irregular pyramid.
- If the base of the pyramid is a square then it is called a square pyramid.
- If the base of the pyramid is a pentagon then it is called a pentagonal pyramid.
- If the base of the pyramid is a circle then it is called a cone or circular pyramid.

**Prism **

- A prism is an important three-dimensional shape. It has two identical shapes facing each other which are called the ‘bases’ of the prism. The other faces of the prism are parallelograms.
- For example, consider the image given below. It is a triangular prism because it has two triangles facing each other and hence these triangles are the bases of the prism. Then, it has three rectangles that are joining together on these two bases.

**Other Types of Prisms **

- Square Prism: It has square bases
- Rectangular Prism: It has rectangular bases
- Pentagonal Prism: It has two pentagons as its bases
- Hexagonal Prism: It has two hexagons as its bases

**Regular and Irregular Prisms and Oblique Prisms**

- When the bases of the prism are regular polygons, it is called a regular prism.
- When the bases of the prism are irregular polygons, it is called an irregular prism.
- In a general prism, the bases are exactly over each other while in an oblique prism, the bases are not exactly over each other.

### Exercise Discussion for RS Aggarwal Class 8 Maths Solutions Chapter 19: Three-Dimensional Figures

- Exercise 19A of RS Aggarwal Class 8 Chapter 19 includes 4 questions. In the first three questions of this exercise, you are given some three-dimensional shapes like cube, cuboid, triangular prism, etc and you have to find the number of faces, number of vertices, and number of edges of each.
- Then, there are four fill-in-the-blanks questions related to edges, vertices, and types of three-dimensional shapes.
- Exercise 19B has 5 questions. Two questions of this exercise are related to Euler’s relation between the number of faces, edges, and vertices of different three-dimensional shapes.
- Then, just like exercise 19A, you are given some three-dimensional shapes and you have to write how many vertices, edges, and faces they contain.

### Benefits of RS Aggarwal Class 8 Maths Solutions Chapter 19: Three-Dimensional Figures by Instasolv

- The RS Aggarwal Solutions for Class 8 Maths Chapter 19 is created to help you grasp all the fundamentals of the chapter easily.
- These solutions contain correct information related to three-dimensional shapes and their properties.
- They are created in sync with the latest CBSE Class 8 Maths syllabus.
- All your doubts regarding the chapter will be cleared with this study material.
- You can access these solutions along with solutions to all other Chapters of RS Aggarwal Class 8 Maths.