Use a single sheet of A4 paper and make a cylinder having the greatest possible volume. The cylinder must be closed off by a circle at each end.
What's the most efficient proportion for a 1 litre tin of paint?
An aluminium can contains 330 ml of cola. If the can's diameter is
6 cm what is the can's height?
There were a number of partial solutions but
this well explained one is almost entirely the work ofAndrei of
Tudor Vianu National College and shows how "obvious" the answer is
with a little visualising and careful reasoning.