if the radius of a circle is decreased 30 % , what happens to the area ?
"area of square = pi * radius ^ 2 new radius = 0.7 * old radius so new area = ( 0.7 ) ^ 2 old area = > 0.49 of old area = > 49 % old area ans : a"
subtract(const_100, multiply(power(divide(30, const_100), const_2), const_100))