有些几何问题中的已知条件之间看似没有联系,如果不能仔细分析,则往往导致解题思路中断.这时,我们可以试将图形的某一部分适当旋转,从而能沟通解题条件,找到解题思路.一、以某线段中点为对称中心例1如图1,ABC中,∠ACB=90°,M为AB中点,∠PMQ=90°,试说明PQ2=AP2+BQ2. There may seem to be no connection between known conditions in some geometric problems, which often lead to interruptions in the problem solving solution if careful analysis is not available. In this case, we can try to rotate a certain part of the figure appropriately to communicate the problem solving conditions and find Problem 1, center point of a line as the center of symmetry Example 1 As shown in Figure 1, ABC, ∠ACB = 90 °, M is AB midpoint, ∠PMQ = 90 °, try to explain PQ2 = AP2 + BQ2.