In 1937 and 1938 Victor Thébault posed three geometric problems that became known as Thébault’s three problems. We state and prove all three. The first two are proved using elementary tools of Euclidean geometry, while the third and most demanding one – the Sawayama–Thébault theorem – requires more: its proof uses homothety, the power of a point and inversion. The central tool is Sawayama’s lemma, which is the key to the proof.
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