Math problem: A rectangular ventilation duct is 30m long and 2mm high, 1.5 decimeter. How many square meters of iron does it take to make 10 section?
Length: 30dm=3m width: 2dm=0.2m height: 1.5 DM = 0. 15m.
(3×0.2+3×0. 15)×2× 10 = 2 1(m？ )
Answer: Does it take 2 1m to make such a rectangular ventilation duct? iron sheet