Question 171836
Well, actually, a three-legged stool will always be more stable (on a perfectly flat floor) than a four-legged stool, why, because it takes only three point to define a plane, and if that plane happens to be a flat floor and the three points happen to be the ends of the legs of a three-legged stool, the the stool will be stable.  With four points (a four-legged stool), one of them could be outside of the plane and thus, contribute to instability of the stool.