I think the problems is you need to know if the region is bounded. If it's on an infinite plane then the probability of the triangle being obtuse aproaches 1.
The reason is simple. Just imagine two points are picked. (A,B) They always form a line. [AB} Now there are two perpendiculars extending from each point. . * . | | | | * | * | * | | A------------------B | | | * | | | . * |
They define two half planes wherein the third point will create an obtuse. That's virtually all the area. Within the two perpendiculars There is a small band of area close th ethe line where the triangle can also be obtuse but the rest is acute.
If the region is bounded then the calculs gets miserable.
Unless I'm just wrong :)
But the odds against that are .9 So I'd say .9 of the time the triangle is obtuse. -- =========--------- - mailto:Sparky@navpoint.com http://navpoint.com/~sparky - ----------=================