In teaching Perimeter and Area ratios of similar figures, I like to begin the lesson by discussing the pricing on pizza sizes.

The price of an 8-inch personal pan pizza might be $5 and the price of a 16-inch large may be $15. At first glance the personal seems like a better deal considering itappears to be half the size of a large, but is just a third of the price. I then show them how that after you find the areas of the two pizzas, the large is actually FOUR TIMES bigger than the personal pan, and is a better deal.