" Using Euler's formula,find "V" if "E=30,F=12

Using Euler’s formula, find V if E = 10, F = 6.

Using Euler's formula,find the unknown:

Using Euler's formula,find the unknown: .

Using Euler's formula find the unknown.

Using Euler's formula find the unknown. F = 20, V =12 , E = ?

Using Euler's formula, find the values of x, y and z

Using Euler's formula find the unknown. F = ? , V = 6 , E = 12

Using Euler's formula find the unknown. F = 5, V = ?, E= 9

Using Euler's formula,find the number of faces if the number of vertices is 6 and the number of edges is 12.