6. The 4-inch radius pizza for $3 or the 8-inch radius pizza for $14.

The 3 dollar pizza is the better deal.

Step-by-step explanation:

I take you mean which is the better deal.

The area of the 4 inch pizza is pi*r^2 = 3.14 * 4^2 = 50.24 square inches.

The area of the 8 inch pizza is pi*r^2 = 3.14 * 64 = 200.96

A square inch of the 4 inch pizza is 3/50.24 = 0.05952 cents

A square inch of the 8 inch pizza is 14/200.96 = 0.0697 cents.

Though this doesn't happen in real life, the smaller pizza is the better buy.