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smc

geometry senior

Problem

A set S consists of triangles whose sides have integer lengths less than 5, and no two elements of S are congruent or similar. What is the largest number of elements that S can have?
(A)
(B)
(C)
(D)
Solution
Define to be the set of all integral triples such that , , and . Now we enumerate the elements of : It should be clear that is simply minus the larger "duplicates" (e.g. is a larger duplicate of ). Since is and the number of higher duplicates is , the answer is or .
Final answer
B