Page 267 - Start Up Mathematics_7

The net of a solid is not unique, for example the triangular pyramid
(tetrahedron) shown in Fig. (iii) above can also be formed by the
adjacent net.

EXERCISE 15.2

1. Complete the following table and verify Euler’s formula in each case.

Faces (F) 6
Edges (E) 9

Vertices (V) 14
F + V – E 2

2. Identify the nets which can be folded to form a cube. (Try with an enlarged copy of the
following nets.)

(a) (b) (c)

(d) (e) (f)

3. Which of these nets will make a triangular prism? Verify by actually drawing enlarged
figures, cutting them and then folding.

(a) (b) (c) (d) (e)

4. Can any of these be a net for a die (cube)? Remember opposite faces of a die always have
a total of seven dots on them. The number written in each square indicates the number of
dots on that face.

2 4 1 2
(a) 3 6 (b) 3 4

1 5 5 6

259