A cylinder can contains lemonade, shown shaded on the diagram in which XY is diameter. What fraction of the volume of the can is filled with lemonade:

just below a quarter; just over a quarter; exactly a quarter?

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.

This problem is taken from the UKMT Mathematical Challenges.

You can find more short problems, arranged by curriculum topic, in our short problems collection.