(define make-point list)
(define get-x car)
(define get-y cadr)
(define (square x) (* x x))
(define (distance x y) (sqrt (+ (square x) (square y))))
(define (pt-distance p) (distance (get-x p) (get-y p)))

(define (get-x-coords pts)
  (map get-x pts))

(define (get-greater-evens pts n)
  (map get-x (filter (lambda (pt) (let ((x (get-x pt))) (and (> x n) (even? x)))) pts)))

(define (get-greater-evens2 pts n)
  (filter even? (map get-x (filter (lambda (pt) (let ((x (get-x pt))) (> x n))) pts))))

(define pts (list (make-point 1 2) (make-point 2 3) (make-point 3 4) (make-point 4 5)))