1) Use Law of Sine on triangles AED and ACD

来源: 于 2011-11-16 20:18:46 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

2) Use AE = AC and the fact that both triangles AED and ACD have a common side AD to get a trigonometric equation

3) Solve the trig equation.