There are several ways to end baseboard. The first is you just mider a 22.5 or 45 degree inside cut and end it like that. Second, you could mider a 45 outside cut and then cut a 45 sliver piece that ends at the wall. Be careful cutting that tiny piece. Lastly, you can buy or build yourself end blocks to whatever shape or size you want, and the base board simple butts up to it. This might look odd if this is the only place you're doing it though. Hope that wasn't to confusing.