古典概型、几何概型是高中阶段重要的知识点,古典概型常用枚举法处理,相对较简单,但是几何概型对“测度”的把握要求较高,常有:长度,面积,体积三种类型,下面举例说明。一、“测度”为长度型例1:已知等腰Rt△ABC中,∠C=90°(图1)(1)在线段BC上任取一点M,求使∠CAM<30°的概率;(2)在∠-CAB内作射线AM,求使∠CAM<30°的概率。 Classical outlines and geometric outlines are important knowledge points in high school. Classical outlines are often enumerated and are relatively simple. However, geometric outlines require a high degree of “measurement”. They are often: length, area , Volume Three types, the following examples. First, “measure” is a length type. Example 1: In known isosceles Rt △ ABC, ∠C=90° (Figure 1) (1) Take any point M on line BC to make ∠CAM<30° Probability; (2) Make ray AM in ∠-CAB and find the probability that ∠CAM<30°.