## Geometry: Common Core (15th Edition)

$_nP_r = \frac{n!}{(n-r)!}$ $_6P_2 = \frac{6!}{(6-2)!}$ $\frac{6!}{4!}$ We also know that: $x! = x(x-1)(x-2)...(1)$ Thus, we have: 6*5 30