If V stands for number of vertices, F stands for number of faces and E stands for number of edges, then :

1. V + F + E = 2

2. F + E - V - 2 = 0

3. F + V - E = 2

4. F - E + V + 2 = 0

If in a polyhedron, number of faces = 12 and number of vertices is 20, then the number of edges is :

1. 10

2. 20

3. 30

4. 40

State the number of faces, number of vertices and the number of edges of :

(i) a pentagonal pyramid

(ii) a hexagonal prism

Verify Euler's formula for the following three dimensional figures :

(i)

(ii)

(iii)