主题：【原创】在一个园上任点三点,求为锐角三角形的概率 (My answer) -- 地下室

第一次发贴。打中文很慢。用英文八。

Let's name the three points A, B and C.

Pick any one, say A, as our starting point. That will not make any difference. Use "|" to indicate if any other point stays in the half circle with A or not.

For the remaining two points, B and C, there are four scenarios with equal probability:

A|BC - sharp triangle

AB|C - sharp

AC|B - sharp

ABC| - obtuse

Obviously, 在一个园上任点三点,求为锐角三角形的概率 is 3/4

Q.E.D.