What is the "Donkey Theorem"? I was watching the Turkish version of Who Wants to Be a Millionaire? and they asked this question: 

What field is the Donkey Case (or I guess it can be translated as Donkey Theorem) related to?

The correct answer was Mathematics. I've never heard of it. What is it?
 A: The donkey theorem is also known as the triangle inequality theorem. It states that in a triangle ABC: a < b + c.
The name comes from the idea that if you have a donkey standing at vertex A, and a hay stack at vertex C, it will ALWAYS be a shorter path for the donkey to go straight from A to C instead of from A to B to C.
This theorem comes in handy when you're trying to find if it's possible to have a triangle with side lengths 44, 32, and 19, for example.
A: The Donkey Theorem is a humorous name for the theorem that triangles can't be proven congruent through ASS (angle, side, side). SSS, ASA, SAS, and AAS can be used to prove congruency because they are static shapes. There are two possible triangles to be made with angle, side, side congruency as shown by the swinging door. 
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A: Alternate interpretation of the case (historical novelty): There is no loop path involving a specific set of 3 land masses and five bridges crossing each bridge only once. (I don't have the link but the original question included a map of a real city on an island).
A: The ASS congruency theorem is an actual true theorem, if you understand it and apply it correctly. (The angle needs to be opposite the longer of the two sides.) If you apply it incorrectly, it only means you weren’t paying attention in geometry class.
