Final answer:
To decide which pizza is the better buy using unit rate, compare the cost per unit of pizza for each option and choose the option with a lower cost per unit.
Step-by-step explanation:
To decide which pizza was the better buy using unit rate, you can compare the cost per unit of pizza for each option.
Lina's method would involve dividing the total cost by the number of pizza slices, while Michael's method would involve dividing the total cost by the total area of the pizza. Whichever option has a lower cost per unit would be the better buy.