# 7. Using Euler’s formula find the unknown.

We know the Euler Formula:

F + V = E + 2:

hence we can easily find the unknown let say 'F, V, and E'

So, For Ist case:

F + 6  = 12 + 2  or  F = 8, hence the number of faces in Ist case is 8.

For IInd Case;

5 + V = 9 + 2   or  V = 6, hence the number of vertices in IInd case is 6.

For IIIrd case;

20 + 12 = E + 2     or   E = 30, hence the number of Edges in the IIIrd case is 30.

 Faces 8 5 20 Vertices 6 6 12 Edges 12 9 30

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