P 19

(4) Enclose a cylinder with a piece of iron 20 cm square, and the side area of this cylinder is 400 cm 2.

Write the answer directly, too much.

2.( 1) Bottom perimeter (2)4*5*2(3) Side area

3.6/2=3 3. 14*3 squared+2 * 3.14 * 3 *1.2 = 50.868.

Without height, this question is wrong.

P20 1。 (1) 4.07,3040,3250,5 liters and 380 ml, (2) bottom area, height, V=SH(3)2,12.56,75.36,75.36? 2.60*4=240 3. 14* 1 squared *5= 15.7.

Tired