#| BEGIN (Write your solution here) |#
(define (make-from-mag-ang m a)
    (define (dispatch op)
    (cond ((eq? op 'real-part) (* m (cos a)))
    ((eq? op 'imag-part) (* m (sin a)))
    ((eq? op 'magnitude) m)
    ((eq? op 'angle) a)
    (else (error "Unknown op: MAKE-FROM-MAG-ANG" op))))
dispatch)
#| END |#