解决几何概型问题的关键是利用已知条件建立适当的几何模型,从建立的几何模型入手,来解决概率问题.本文以“面积型”几何概型的几个典型问题说明如何解决此类问题.例1在面积为S的ABC内任选一点P,则PBC的面积小于2S的概率是.解如图1所示,EF为ABC的中位线,当点P位于四边形BEFC内 The key to solve the problem of geometric model is to use the known conditions to establish the appropriate geometric model and to start with the established geometric model to solve the problem of probability.This paper describes how to solve such problems with several typical problems of " Example 1 The probability of an area of ​​PBC less than 2S is P, if P is selected within ABC of area S. Solution As shown in Fig. 1, EF is the median line of ABC, and when point P is located within the quadrilateral BEFC