Since the Han dynasty (206 BC - 220 AD), the ancient Chinese have been erecting mining derricks to extract salt and other minerals from deep underground. Resting in the middle of these derricks is a 1.8 m
cylindrical drum with a diameter measuring 0.6 m
. Bamboo cables were used to lower the drill bits. The diameter of the bamboo cable is 1 cm
. If the cylindrical drum is tightly wound by this strong cable five times, how long is the bamboo cable around the cylindrical drum to the nearest metre?
NOTE: Treat the layers of the cable to be exactly on top of each other.