Since we know that length is twice the width, we can say that:
Perimiter = 2(twice the width) + 2(width)
Therefore, P = 2(2w) +2(w)
this simplifies to P=6w
Sine P=180, 160 = 6w, so w = 30
Because length is twice the width, length = 2 * width, or 2*30, which is 60
Therefore:
length = 60
width = 30
