A farmer owns a round barn of radius 12m. A goat is attached by a rope at a fixed point on the wall outside the barn (see image).
The farmer wants to make sure that it can only graze an area equal to that of the barn. How long should the rope be?
For this (very) hard math puzzle, you may enter your answers into the comment section below. Depending on how many solvers we get, will aim to unmask next week!