Question

Use eulers formula to find the missing number.

Edges: 49
Faces:21
Vertices:?
30
32
26
28

Answer 1

30

Explanation:

Euler's Formula: F(aces) + V(ertices) = E(dges) + 2 or F + V = E + 2

21 + V = 49 + 2

21 + V = 51 Subtract 21 from both sides.

V = 30

Answer 2

The formula states that:

Faces + Vertices - Edges = 2

So 21 + V - 49 = 2 => V = 2+49-21 = 30

Answer A!