Problem: the radius of the two circular fields is in the ratio 4 : 5 the area of the first field is what percent less than the area of the second ?
Rationale: "r = 4 ï € r 2 = 16 r = 5 ï € r 2 = 25 25 ï € â € “ 9 ï € 100 - - - - ? = > 36 % . answer : d"
annotated_formula: subtract(power(5, const_2), power(4, const_2))