Question 9 3.14× 20× 30+3.14× (20 ÷ 2) 2× 2-78.5× 2 = 2355 (cm? )

10 problem 3.14× (12× 3/4 )×12+3.14× (12× 3/4 ÷ 2). 705 (square decimeter)

1 1 problem (1)12×12× 410 3.14×12.

12 problem188.4 (2× 3.14× 2) =15 (DM)

13 question 3.14× 0.32× 2× (4-1) =1.6956 (square meter)

14 suppose that the diameter of the bottom surface of the cylinder is D and the height is H. Because the lateral expansion of the cylinder is square, D; h=d:πd= 1:π.

I wish you progress in your studies, qwq.