This one comes courtesy of Mystery Fred. The diagram above is for a Circle Gaps Brainteaser, and appeared online last week as part of Double Helix, CSIRO‘s science magazine for kids. The text for the brainteaser (as if it matters) is as follows:
What is the area of the orange star in the centre? The blue circles each have an area of 3 square centimetres, and the big square has sides that are 4 centimetres long.
A comment on the post makes it clear that the choices of sidelength and area were purposefully made.