20 circular plates each of radius 7 cm and thickness 1.5 CM are placed one above the other find the volume of the solid so formed​

4618.14cm^3(rounded to 2dp)

Explanation:

20*1.5=30cm (total height)

π*r^2*h⇒  π*7^2*30

                             =4618.14cm^3(rounded to 2dp)

answer; (b); i believe its indefinite existence of human population in a healthy and prosperous condition;