Short answer: the rectangle is a square, so the length and width are ... (316 m)/4 = 79 m.
_____ Let x represent the length of the rectangle. Then the width in meters is 316/2 -x. The area is the product of length and width. area = x(158 -x) This is the equation of a parabola that opens downward. It has zeros at x=0 and x=158. The vertex is on the line of symmetry, halfway between the zeros, at x=79.
