if the radius of a circle is decreased 40 % , what happens to the area ?
"area of square = pi * radius ^ 2 new radius = 0.6 * old radius so new area = ( 0.6 ) ^ 2 old area = > 4 / 25 of old area = > 36 % old area ans : e"
subtract(const_100, multiply(power(divide(40, const_100), const_2), const_100))