1: ① 圆 侧 ② 25.12 50.24 150.72 251.2 301.44 100.48 ③ 4
2: ① C ② B ③ C ④ A
3: 图一 表面积 5÷2=2.5 2.5 ×3.14×2+5×3.14×3 =6.25×3.14×2+5×3.14×3 =39.25+47.1 =86.35
体积 2.5 ×3.14×3 =6.25×3.14×3 =58.875
图二(本答案出自零五网) 6 ×3.14×6÷3 =36×3.14×6÷3 =226.08
4: 18×20×7.8=2808 |