線段 BD 平分角ABC, 若 AD= 9, DC=7, 求ABD 的面積??
原版的英文題目
4. In triangle ABC, side AC and the perpendicular bisector of BC meet at point D, and BD bisects angle ABC. If AD = 9 and DC = 7, what is the area of triangle ABD?
更新1:
D 是BC中垂線和AC的交點 (不是兩條中垂線的交點)