Maths 3 Mark Question

Euler's relation is:
F - E + V = 2
A tetrahedron:
Number of faces = F = 4
Number of edges = E = 6
Number of vertices = V = 4
⇒ (F - E + V) = 4 - 6 + 4 = 2

Euler's relation is:
F - E + V = 2
A cube:
(There is an error in this question. It should have been a square prism rather than square.)
Number of faces = F = 2 squares + 4 rectangular = 6
Number of edges = E = 12
Number of vertices = V = 8
⇒ (F - E + V) = 6 - 12 + 8 = 2

Euler's relation is:
F - E + V = 2
A triangular prism:
Number of faces = F = 2 triangular + 3 rectangular = 5
Number of edges = E = 9
Number of vertices = V = 6
⇒ (F - E + V) = 5 - 9 + 6 = 2

Euler's relation is:
F - E + V = 2
A square pyramid:
Number of faces = F = 2 triangular + 3 rectangular = 5
Number of edges = E = 8
Number of vertices = V = 5
⇒ (F - E + V) = 5 - 8 + 5 = 2