The length of a rectangle is three times longer than its width. the perimeter of the rectangle is 16 feet. if x represents the width of the rectangle, which equation can be used to find its value?

Given that x represents the width of the rectangle and that the length of the rectangle is three times longer than the width. Then the length is 3x. The perimeter of a rectangle is given by 2(length + width) = 2(3x + x) = 2(4x) = 8x. The perimeter of the rectangle is 16 feet. Therefore, the required equation is 8x = 16.