#| BEGIN (Write your solution here) |#
(define (estimate-integral p x1 x2 y1 y2 trials)
  (define (experiment)
    (let ((x (random-in-range x1 x2))
          (y (random-in-range y1 y1)))
      (and
       (>= x x1)
       (<= x x2)
       (>= y y1)
       (<= y y2))))
  (let ((fract (monte-carlo trials experiment)))
    (* (- x2 x1)
       (- y2 y1)
       fract)))
#| END |#