The square with the straightest diagonal has the largest area. Is the area d? 0? 5/2, length-width ratio 1.

2

Let the height be x and the width be kx(k= in).

And kx? 0? 5 = 4840S =(x 16)(kx 10)= kx？ 0? 5 16kx 10x 160 = 5000 16kx 10x = 5000 16kx 48400/kx

If and only if 16kx=48400/kx, the area is the smallest. At this time, kx=55 and S=6760.