a rope of which a calf is tied is increased from 5 m to 9 m , how much additional grassy ground shall it graze ?
"π ( 92 – 52 ) = 176 answer : c"
multiply(subtract(power(9, const_2), power(5, const_2)), divide(add(multiply(5, const_2), const_2), add(const_4, const_3)))