The Pythagorean theorem, or a²+b²=c², states that in a right triangle, the sum of the squares of the two legs (shorter sides) equal the square of the longest side. Plugging 6 and 8 in, we get 6²+8²=36+64=100=c². Getting the square root of both sides, we get √100=c=10 as the length of the longest side
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