Page 83 - Maths Class 06

Three-Dimensional Shapes
We see solids all around us in all sorts of shapes and sizes. Some have regular dimensions and these are
the ones we shall study first. Some of these are spheres, cones, cylinders, cubes, cuboids and pyramids.

Ball
This is a sphere.
Geometry box
Playing dice This is a cuboid.
This is a cube. Can Clown cap
This is a cylinder. This is a cone.

Tent
This is a prism. This is a pyramid. This is also a pyramid.
Fig. 5.20
Just like flat figures, i e. . polygons have sides and vertices, solid figures have faces, edges and vertices.

Look at the picture of a cube.
Each side of a cube has a flat surface or face. A cube has 6 faces. Vertex
Two faces meet in a line segment which is called an edge.
Face
A cube has 12 edges.
Edge
Three edges meet in a point which is called a vertex.
A cube has 8 vertices. Fig. 5.21

u Each edge of a cube has equal length.
u A cuboid also has 6 faces, 12 edges and 8 vertices.

Let us look at pyramids shown in the figures given below. One has a square base, the other has a
triangular one. The other three/four faces of a pyramid are triangles that meet in a point.
A pyramid whose base is a square is known as a square pyramid.
A pyramid whose base is a triangle is known as a triangular pyramid.

(i) Square pyramid (ii) Triangular pyramid (iii) Prism
Fig. 5.22
Face-5 Faces-4 Faces-5
Edges-8 Edges-6 Edges-9

Vertices-5 Vertices-4 Vertices-6

83