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旋转变换是几何变换中的几种基本变换之一.本文谈谈巧用旋转法解几何题.一、旋转的特征(1)图形中的每一点都绕着旋转中心旋转了同样大小的角度;(2)对应点到旋转中心的距离相等;(3)对应角、对应线段相等;(4)图形的形状和大小都不变.二、适合用旋转法解决的几类问题1.正三角形类例1如图1,设P是等边△ABC内的一点,PA=3,PB=4,PC=5,∠APB的度数是
Rotation transformation is one of the basic transformations in geometric transformation. This article talks about using the rotation method to solve geometric problems. First, the rotation characteristics (1) Each point in the graph rotates around the rotation center by the same size angle; (2) The distance from the corresponding point to the center of rotation is equal; (3) The corresponding angle and the corresponding line segment are equal; (4) The shape and size of the figure are unchanged. Second, several types of problems that are suitable for solving with the rotation method 1. The positive triangle Example 1 is shown in Fig. 1. Let P be a point in the equator △ ABC, PA=3, PB=4, PC=5, the degree of ∠APB is