geo.hs

import Geometry

main = do
  print $ sphereVolume 4.0

Geometry.hs

module Geometry
( sphereVolume
, sphereArea
, cubeVolume
, cubeArea
, cuboidArea
, cuboidVolume
) where
  sphereVolume :: Float -> Float
  sphereVolume radius = (4.0 / 3.0) * pi * (radius ^ 3)
  sphereArea :: Float -> Float
  sphereArea radius = 4 * pi * (radius ^ 2)
  cubeVolume :: Float -> Float
  cubeVolume side = cuboidVolume side side side
  cubeArea :: Float -> Float
  cubeArea side = cuboidArea side side side
  cuboidVolume :: Float -> Float -> Float -> Float
  cuboidVolume a b c = rectArea a b * c
  cuboidArea :: Float -> Float -> Float -> Float
  cuboidArea a b c = rectArea a b * 2 + rectArea a c * 2 + rectArea c b * 2
  rectArea :: Float -> Float -> Float
  rectArea a b = a * b