Pizzas put in square box

1. Why are round pizzas put in square boxes?

2. If a deaf person must appear in court is it still called a hearing?

3. Why does the sign read, “Enter at your own risk" who else could you risk other than yourself?

4. If it's called "frying pan" is it OK to boil something in it?

5. Why doesn't every doughnut have nuts in it?