11.How are the circumference and the diameter of any given circle related
12. The diameter of a circle is 22 cm long. What is its area?
13.What is the area of the largest circle that can be drawn on a square paper whose side is 20 cm? *
16. Two workers need to dig a rectangular pit that is 2 meters long, 1.5 meters wide, and 1 meter deep. How many cubic meters of soil must they remove? *
17.A cubical water tank has a 20 cm edge. How much water can it contain?