#| BEGIN (Write your solution here) |#
(define (random-range-stream low high)
  (cons-stream (random-in-range low high)
               (random-range-stream low high)))

(define (estimate-integral proc x1 x2 y1 y2)
  (define point-in-stage-stream
    (stream-map proc (random-range-stream x1 x2) (random-range-stream y1 y2)))
  (monte-carlo point-in-stage-stream 0 0))
#| END |#