if the diameter of circle r is 40 % of the diameter of circle s , the area of circle r is what percent of the area of circle s ?
"let diameter of circle r , dr = 40 and diameter of circle s , ds = 100 radius of circle r , rr = 20 radius of circle s , rs = 50 area of circle r / area of circle s = ( pi * rr ^ 2 ) / ( pi * rs ^ 2 ) = ( 20 / 50 ) ^ 2 = ( 4 / 10 ) ^ 2 = 16 % answer : a"
divide(multiply(circle_area(40), const_100), circle_area(const_100))