it is important to note that the perimeter is equal to 2(width) + 2(length). let's call width w and length L.
so 294 = 2w + 2L
but the length is two times the width, so L=2w.
294 = 2w + 2(2w)
294 = 2w + 4w
294 = 6w
divide both sides by 6 to solve for w.
49 = w. so our width is 49 feet.
L = 2w, so L = 2(49). L = 98.
our length is 98 feet.