Answer:
length = 36 in and width = 6 in
Step-by-step explanation:
let width be w then length (l) = 6w
perimeter = 2l + 2w = 2(6w) + 2w, that is
perimeter = 12w + 2w = 84, so
14w = 84 ( divide both sides by 14 )
w = 6
Thus
width = 6 in
length = 6w = 6 × 6 = 36 in