Let be a square with points and on and respectively, such that and
If the area of can be written as , where and are coprime positive integers, find the value of
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I thought this was a really nice question.
We have ∠ C E F = 9 0 ∘ − ∠ D E A − ∠ A E D , and ∠ A D E = ∠ E C F = 9 0 ∘ . Thus, Δ A D E ∼ Δ E C F . Comparing proportional sides, we have A E A D = E F E C , so A D = 3 4 E C , so A D = 4 D E . We also have A D 2 + D E 2 = A E 2 , so 1 7 D E 2 = 1 6 . Thus, D E = 1 7 4 , so A D = 1 7 1 6 . Thus, the area of the square is A D 2 = 1 7 2 5 6 . Thus, the answer is 2 5 6 + 1 7 = 2 7 3 .