# 7th Class Mathematics Visualising Solid Shapes

Visualising Solid Shapes

Category : 7th Class

Visualising Solid Shapes

• Description of Some Basic Shapes:

(i) Square

It has four sides and four corners.

All its sides are of the same length.

(ii) Rectangle

It has four sides and four corners.

The opposite sides of a rectangle are of the same length.

(iii) Triangle

It has three sides and three vertices.

(iv) Cuboid

It has 6 flat faces, 12 straight edges and 8 vertices.

(v) Cube

(vi) Cylinder

It has 3 faces

$\to$

1 curved face and 2 flat faces.

It has 2 curved edges.

(vii) Cone

It has 2 faces

$\to$

1 curved face and

It has 1 curved edge.

• Three dimensional shapes have length, breadth and height or depth.
• Two-dimensional shapes have only length and breadth.
• Three-dimensional (or 3 - D) shapes can be visualised on a two-dimensional (or 2-D) surface.
• A net is a skeleton-outline in 2 - D which when folded results in a 3-D shape. The same solid can have several types of nets.
• Dice are cubes with dots on each face. Opposite faces of a die always have a total of seven
• Dots on them. Some dice have number, 1 to 6 on their faces.
• A solid can be sketched in two ways.
• An oblique sketch which does not have proportional lengths, but conveys all important aspects of the appearance of the solid.
• An isometric sketch, drawn on an isometric dot paper, which has proportional measurements of the solid.
• Different sections of a solid can be viewed in many ways:
• Slicing the shape results in the cross-section of the solid.
• Observing a 2-D shadow of a 3-D shape.
• Looking at the shape from different angles, i.e., the front-view, the side-view and the top-view.

• Description of few more solid shapes

 S.NO. Name of figure Figure Description Components 1. Triangular Prism A Triangular resembles a kaleidoscope. Faces: 5 Edges: 9 Vertices: 6 2. Triangular Pyramid or Tetra- hedron It has a triangular base. Faces: 4 Edges: 6 Vertices: 4 3. Square Pyramid It has a Square as its Faces: 5 Edges: 8 Vertices: 5 4. Sphere NO Flat face. It has only a spherical face. Faces: 1 Edges: 0 Vertices: 0

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