# Thread: Problem of the month

1. ## Problem of the month

How many planes would by formed by n non-collinear and non-coplanar points?

2. ## Binomial

Since three non-collinear points define a plane, this is just the number of cominations of three points we can choose from the n, which is $\binom{n}{3}=\frac{n!}{3!(n-3)!}=\frac{n(n-1)(n-2)}{6}$.

-Kevin C.