Nataliya D. answered 02/09/13
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→→→→→→→→→→→→→→→→
↓ l ↓
↓ ↓
↓ w w ↓
↓ ↓
↓ l ↓
→→→→→→→→→→→→→→→→
P = l + w + l + w = 2 · l + 2w if l = 2 + w , then
↓
P = 2 · (2 + w) + 2w = 4w + 4 = 4(w + 1) = 84, then
w + 1 = 84/4 --------> w +1 = 21 -----> w = 20 ft. and l = 22 ft.