16, surface area: 20 * 20 * 5 squared+3.14 * 20 * 20 ÷ 2+3.14 *10 = 2942 (square centimeter).

Volume: 20*20*20+3. 14* 10 squared * 20 ÷ 2 = 1 140 (cubic centimeter).

17, * * 10 cubic volume 5 * 5 * 10 = 1250 (cubic centimeter) surface area 5*5*34=850 (square centimeter).

18, omitted,