;; constant
(define PI 3.142)

;; square : number -> number
(define (square x) (* x x))

;; area-circle : number -> number
(define (area-circle radius)
  (* PI (square radius)))

;; circumference-circle : number -> number
(define (circumference-circle radius)
  (* 2 PI radius))

;; area-cylinder : number number -> number
;; 2(pi r^2) + (2 pi r)h
(define (area-cylinder radius height)
  (+
   (* 2 (area-circle radius))
   (* (circumference-circle radius) height)))