三角形的一边与另一边的延长线组成的角叫做三角形的外角.三角形的一个外角等于和它不相邻的两个内角的和.灵活利用这个性质将问题转化,能迅捷地解答一些与角有关问题.一、与角有关求值问题例1如图1,AD是△ABC的外角∠CAE的平分线,∠B=30°,∠DAE=65°,则∠ACD的度数是 The angle between one side of the triangle and the other side is called the outer angle of the triangle, and the outer angle of the triangle is equal to the sum of the two inner angles that are not adjacent to it. Flexible use of this property transforms the problem, Problem 1. Evaluating Problem with Corner Example 1 As shown in Fig. 1, AD is the bisector of the outer corner ∠CAE of △ ABC, ∠B = 30 ° and ∠DAE = 65 °, then the degree of ∠ACD is