the sector of a circle has radius of 21 cm and central angle 120 o . find its perimeter ?
"perimeter of the sector = length of the arc + 2 ( radius ) = ( 120 / 360 * 2 * 22 / 7 * 21 ) + 2 ( 21 ) = 44 + 42 = 86 cm answer : d"
multiply(multiply(const_2, divide(multiply(subtract(21, const_3), const_2), add(const_4, const_3))), 21)