the ratio of the radius of two circles is 2 : 7 , and then the ratio of their areas is ?
"r 1 : r 2 = 2 : 7 î r 1 ^ 2 : î r 2 ^ 2 r 1 ^ 2 : r 2 ^ 2 = 4 : 49 answer : d"
divide(circle_area(2), circle_area(7))