如果不用輔助線：這些三角形麵積一樣,ABE,ABD,ADC. 知道ADE是9.BEC麵積=21×12/9.

來源: got66 於 2026-03-21 06:22:05 [舊帖] [給我悄悄話] 本文已被閱讀：次

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