The length, l, of a rectangle is modeled by the equation l = w + 4, where w is the width of the rectangle in centimeters. two equations have been determined that represent the area of the rectangle, a, in square centimeters: the first equation was created using the formula for the area of a rectangle: a = w2 + 4w. the second equation models the relationship between the rectangle's area and width: a = 4w + 45.