As shown in the figure, △ ABC is an equilateral triangle, points D and E are on AB and AC respectively, and F is the intersection of be and CD. It is known that ∠ BFC = 120 °. Verification: ad = CE

It is proved that: ∵ - BFC = 120 °, ∵ - ECF = ∵ BFC - ∵ CEB = 120 ° - ∵ ABC is equilateral triangle, ∵ - EBC = 180 ° - 60 ° - ∵ CEB = 120 ° - ∵ - ECC, ∵ ECF =

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