三角形全等的判定在几何推理中应用十分广泛,是一个不容忽视的知识点。 一、选择正确的方法,判定两个三角形全等 例1.如图1,O是AB中点,∠A=∠B,△AOC与△BOD全等吗?为什么? 分析:已知O是AB的中点,所以,OA=OB,又有∠A=∠B,但两个条件不足以证明△AOC与△BOD是否全等,要注意结合图形发现隐含条件,即对 The determination of triangle congruence is widely used in geometric reasoning and is a knowledge point that cannot be ignored. First, select the correct method to determine the two triangles Congruent Example 1. As shown in Figure 1, O is the AB midpoint, ∠A=∠B, △AOC and △BOD congruent? Why? Analysis: Known O is AB The middle point, therefore, OA = OB, there are ∠ A = ∠ B, but the two conditions are not sufficient to prove whether △ AOC and △ BOD are equal, pay attention to the combination of graphics to find hidden conditions, that is,