Bottom area: 3. 14 × 4? = 50.24 square centimeters

Volume: 50.24 × 125 = 6 280 cubic centimeters.

Length: 6 280 ÷ 5? = 25 1.2 cm

2.*** Take away:16× 7 =112kg.

Keep the original weight of three bags, and take away the original weight of 7-3 = 4 bags.

Weight of each bag: 1 12 ÷ 4 = 28kg.

3. Smile and walk every hour 1/6, and Mei Mei walk every hour 1/4.

Meeting time:1÷ (1/6+1/4) =12/5 hours.

Xiaoxiao is gone: 12/5 × 1/6 = 2/5.

Mei Mei left: 12/5 × 1/4 = 3/5.

Mei Mei traveled more than Xiao Xiao by 3/5-2/5 = 1/5.