A cylindrical glass is half full of water. If you tilt the glass until the water level reaches the exact brim without spilling a single drop, the water forms a triangle shape when viewed from the side. What is the angle of tilt from the vertical table surface?
45 degrees
When a half-full cylinder is tilted so the water line touches both the bottom edge and the top opposite edge, the water forms a right-angled isosceles triangle inside the cylinder. The angle of the water surface relative to the base of the cylinder is 45 degrees.
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Hard. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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