Question 971723
a) 15 foot diameter means we have a 7.5 foot or 90 inch radius, then
Volume(V) = pi * 90 * (1/8) =  35.342917358 cubic inches
there are 1.8 cubic inches in a liquid ounce, therefore
you need 35.342917358 / 1.8 = 19.6 liquid ounces or 2.5 liquid cups
b) 18 foot diameter means we have a 9 foot or 108 inch radius, then
Volume(V) = pi * 108 * (1/8) = 42.411500829 cubic inches
there are 1.8 cubic inches in a liquid ounce, therefore
you need 42.411500829 / 1.8 =  23.6 liquid ounces or 3 liquid cups