#| BEGIN (Введите свое решение) |#
 (define (make-point x y)
  (cons x y)
  )

(define (x-point point)
  (car point)
  )
(define  (y-point point)
  (cdr point)
  )

(define (make-segment p1 p2)
  (cons p1 p2)
  )
(define (start-segment segment)
  (car segment)
  )
(define (end-segment segment)
  (cdr segment)
  )
(define (midpoint-segment segment)
  (make-point
    (/ (+ (x-point (start-segment segment))
          (x-point (end-segment segment)))
       2)
    (/ (+ (y-point (start-segment segment))
          (y-point (end-segment segment)))
       2)
    )
  )
 
#| END |#