Question

A hollow metal pipe has an external radius of 5cm and an internal radius of of 4.5cm. If the pipe is 1m long, find the volume of the metal used to make the pipe.
I am really confused how to begin to solve this, can someone help please?

Answer 1

Take the total volume of the pipe (the full radius of 5cm) and you will have to find the volume of the smaller pipe size with radius 4.5 cm
Volume of metal = total volume of large pipe - (volume of internal pipe with radius 4.5 cm)

So in conclusion... find both volumes then take the smaller volume away from the larger one :)

Answer 2

Do you subtract it.