; clock angles

(define (angle hr min)
  (let ((hour (* (/ 360 12) (+ hr (/ min 60))))
        (minute (* (/ 360 60) min)))
    (exact->inexact (abs (- hour minute)))))

(display (angle 12 00)) (newline)

(define (angle hr min)
  (let ((hour (* (/ 360 12) (+ (if (= hr 12) 0 hr) (/ min 60))))
        (minute (* (/ 360 60) min)))
    (exact->inexact (abs (- hour minute)))))
    
(display (angle 12 00)) (newline)
(display (angle 12 01)) (newline)
(display (angle  6 00)) (newline)
(display (angle  3 45)) (newline)