Read the description of a proportional relationship. Ever since Brian was a small child, his favorite food has always been carrots. He likes them so much he wants to plant a garden in his backyard just to grow carrots. There is a proportional relationship between the size of Brian's garden (in square feet), x, and the number of carrots he can grow at a time, y. The equation that models this relationship is y=4x. What size garden does Brian need to grow 20 carrots at a time?