Arectangular napkin costs $3.25. a similar tablecloth is five times longer and five times wider. how much would you expect to pay for the tablecloth?

We let the price of each napkin be dependent on its area, A. The area of a tablecloth which is a rectangular piece is calculated through the equation,
                                         A2 = LW
                                         A2 = (5l)(5w) = 25lw = 25A
Hence, multiply the cost of each napkin by 25 to get the estimated cost for each tablecloth. The operation gives an answer of 81.25. Each tablecloth is expected to cost $81.25. 

When buying cloth, you're paying for the area. You would need to take the cost multiplied by the area. To start with, you would need to multiply the length and width, in this case, 5x5=25. Take the price and multiply by the area, and that would be your answer. 
$3.25x25=$81.25.