解答

✨ 最佳解答 ✨

假設 DF = x => AD = (7-x)

BF : BD = BE : BC = BD : BA
9 : (9+x) = BE : BC = (9+x) : 16
=> x = 3 = DF

BD = 9 + 3 = 12

oops.

哦莫謝謝了😆

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