A hemispherical bowl has an internal radius of 21 cm. How many litres of soup can it hold? (Use π = 22/7, and 1000 cubic cm = 1 litre.)

Capacity = (2/3)π$r^3=(2/3)\times (22/7)\times 9261=19404$ cubic cm, and dividing by 1000 gives 19.404 litres. The trap 38.808 uses the whole sphere (4/3)π$r^3$, but a bowl is only half of one; 9.702 uses (1/3)π$r^3$, halving a second time; 29.106 uses π$r^3$ with no fraction at all.