Visualising Solid Shapes Class 7 Notes: Chapter 15

Visualising solid shapes class 7 notes provided here are one of the most important resources for the students of class 7. These CBSE class 7 notes for chapter 15 will not only help the students to learn the concepts easily but will also help them to revise this topic in a more efficient way. The different topics from this chapter that are included here are-

  • What are solid shapes and plane figures?
  • Faces, edges, and vertices of a solid shape
  • Types of sketches of a solid
  • Ways of viewing a solid shape
  • Practice Questions

What are Solid Shapes and Plane Figures?

Plane figures are of two dimensions i.e. 2D and they have only length and breadth. On the other hand, solid shapes are three dimensional shapes which means they have height, breadth, and length. A few examples of plane figure are circles, squares, triangles, etc. and examples of solid shapes or 3D shapes are sphere, cuboid, pyramid, etc.

Faces, Edges, and Vertices of a Solid Shape

Faces, edges, and vertices are terms associated with 3D shapes and they refer to as-

  • Faces – the flat surfaces of a solid shape are its faces
  • Edges – the line segments of a solid shape’s skeleton are its edges
  • Vertices – the corner of a solid shape are its vertices

Edges, vertices, and faces of common 3D shapes:

Shape Name Vertices Edges Faces
Cube and Cuboid 8 12 6
Prism 6 9 5 (2 triangle + 3 rectangle)
Pyramid 5 8 5
Cylinder 0 2 3 (2 circle + 1 curved)
Cone 1 1 2 (1 circle + 1 curved)
Sphere 0 0 1

Types of Sketches of a Solid

Two types of sketches of a solid shape or 3D shape are possible which are-

  • Oblique Sketch – it does not have proportional lengths
  • Isometric Sketch – it has proportional lengths

It should be noted that solid shapes can be drawn on papers as a 2D model. This representation of a 3D shape into a 2D shape is known as 2-D representation of a 3-D solid.

Ways of Viewing a Solid Shape

The three most common ways of viewing a solid shape are-

  1. Slicing of cutting the shape which shows the cross section of the solid
  2. Observing 2D shadow of a 3D shape
  3. Visualising the solid shape from front-view, side-view, and top-view

Practice Questions

  1. A cuboid has the dimensions of 5 cm, 3 cm and 2 cm. Draw three different isometric sketches of this cuboid.
  2. Three cubes having 2 cm edge each are placed side by side to form a cuboid. Sketch an oblique and isometric sketch of this cuboid.
  3. Write true or false – (i) a cube can cast a shadow in the shape of a hexagon, (ii) a cube can cast a shadow in the shape of a rectangle.

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Practise This Question

You have to select the players for your football team. Which of the following given data sets will help you to take the decision?

Data set 1. Name of the players

Data set 2. Height of the players

Data set 3. Stamina of players

Data set 4. Nationality of the players