[Haskell-beginners] "Delegating" class instance definition

[Nicolaas du Preez]

data Cycle = Cycle { name :: String, size :: Double } deriving (Eq, Show)

instance Ord Cycle where
	(<) a b = (<) (size a) (size b) -- problem statement!
	…

How can I specify that, on the right-hand side of the problem statement, I refer to (<) :: Double -> Double -> Bool instead of (<) :: Cycle -> Cycle -> Bool?

Is there another way to state that "Cycle is an instance of Ord based on size"?