Actually if you are into new age type stuff (which I'm not) the five-pointed star is a pentagram with the five rays representing the energy of the four elements; earth, air, fire and water. The fifth arm of the pentagram is symbolic of spirit or "soul". Of course in cheesy witchcraft movies there are always ritualistic sacrifices going on in a pentagram.

My interest is more on the mathematical side. A lot of architecture and art have proportions based on the ratio Phi sometimes referred to as the golden ratio. As it turns out the pentagram is constructed from golden ratio triangles and can visually represent Fibonacci sequences.

Link below if you a more into Fibomacci numbers than ritualistic sacrifices