If a regular graph of order 3 is planar how many faces should it have?

Question

I have reasoned in this way. Since it has to be regular and planar with 3 vertices we would get a triangle. So it should have an inner face and an outer face. Is that correct or I have misunderstood the question that seems very simple to me?

Answer 1

Euler's formula is $$V-E+F=2\tag{1}$$

The handshaking lemma says that twice the number of edges is the sum of the vertex degrees. In this case$$E={3V\over2}\tag{2}$$ Putting $(1)$ and $(2)$ together gives $$F={V\over2}+2$$