I want to prove the inverse theorem of Menelaus theorem

A. Saiwa theorem: O is any point in △ ABC, Ao extends BC to D, Bo extends AC to e, CO extends AB to F, then (AF / BF) & ﹥ 8226; (BD / CD) & ﹥ 8226; (CE / AE) = 1, as shown in Fig. 4. It is proved that in △ AOB, of ∠ AOB, from the angle theorem → AF / BF = (sin ∠ AOF / sin ∠ BOF) & ﹥ 8226; (AO

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