there are two concentric circles with radii 6 and 4 . if the radius of the outer circle is increased by 50 % and the radius of the inner circle decreased by 25 % , by what percent does the area between the circles increase ?
"the area of a circle is pir ^ 2 , where r is the radius . the area of the big circle is 36 pi . the area of the small circle is 16 pi . the area a 1 between the circles is 20 pi . when the big circle ' s radius increases , the new area is 81 pi . when the small circle ' s radius decreases , the new area is 9 pi . the area a 2 between the circles is 72 pi . the ratio of a 2 / a 1 is 72 / 20 = 3.6 which is an increase of 260 % . the answer is c ."
multiply(divide(subtract(subtract(power(multiply(6, divide(add(const_100, 50), const_100)), const_2), power(multiply(4, divide(subtract(const_100, 25), const_100)), const_2)), subtract(power(6, const_2), power(4, const_2))), subtract(power(6, const_2), power(4, const_2))), const_100)