We have two responses for you

Maryjane,

This is a well-known trick question. It is not really mathematics, because the best one can do without the trick is easily seen to be 7 pieces. The trick: cut the pizza into 4 pieces with 2 cuts, then pile the 4 pieces on top of one another before making the third cut.

Chris

Think three-dimensionally, Maryjane. Some people like crust and some people like topping (hopefully half and half)! This probably works best with a deep dish pizza.

Is this enough of a hint for you?
Stephen.