I like Guest's statement of the conclusion of the Pythagorean Theorem though I suggest a modification: The area of the circle on the hypotenuse is equal to the sum of the areas of the circles on the other two sides.
My problem is unfair and if I were grading it I would give full credit for the answer, 20. But I would give extra credit for the right answer, though I would expect people who lived on farms would have a huge advantage. Those folks have swung open fence gates and plowed fields and so they have a better chance of really thinking about what "uniform width" means. In my defence, I did say that the problem was posed in honor of Pi day, so you'd expect the answer to have Pi in it.