全等三角形知识是初中几何的重点,是研究图形性质的基础,在几何证题中有着广泛的应用.下面举例说明其具体应用.1.证线段相等例1如图1,在正方形ABCD的边BC、CD上取E、F两点,使∠EAF=45°,AG⊥EF于G.求证:AG=AB.证明:将△ABE以A点为原点逆时针旋转90°,得到△ADH,可证△AHF≌△AE Congruent triangle knowledge is the focus of junior high school geometry. It is the basis for studying the nature of graphs. It has a wide range of applications in geometrical proofs. The following example illustrates its specific application. 1. The line segment equals example 1 as shown in Figure 1, on the side of the square ABCD BC, CD take E, F two points, so that ∠ EAF = 45 °, AG ⊥ EF in G. Proof: AG = AB. Proof: △ ABE with point A as the origin counterclockwise rotation 90 °, get △ ADH, Proof △AHF ≌△AE