Square or Round - which pizza should I buy?

Warm up for π day with this updated activity! Subway has great Flatizzas but Sbarro's pizzas are good too.

If that slice from Sbarro is from an 18-inch pizza cut into eight pieces, which deal is better when comparing the area of the pizzas and their cost? 

(Note: We're not considering the pizza's volume. We're only dealing with its surface area.)  How does the area of a square pizza compare to the area of a circular pizza? Technology: As students grapple with comparing the area of a square and the area of a circle with the same diameter/side length have them explore this Geogebratube app on area relations.

For Adventurer members we have an editable Word docx and solutions.