② 25. 12 50.24 150.72 25 1.2 30 1.44 100.48

③ 4

2: ① C ② B

③ C ④ A

3: Figure 1

superficial area

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

roll

2.5×3. 14×3

=6.25×3. 14×3

=58.875

Figure ii

6×3. 14×6÷3

=36×3. 14×6÷3

=226.08

4: 18×20×7.8=2808

You will be smart if you do it independently in the future ~ ~ ~ You can do it! Trust me! ! ! ! ! It's not easy for me either. Adopt it ~ ~ ~

If you have any questions about exercises and exams in the future, I will definitely answer them!