I want to talk to this girl, but I dont know if she has a boyfriend...How do I find out?

I go to school with this girl and I run cross country and she is on the girls team. She's pretty cute and I've had a few quick conversations with her, but I want to really talk to her and maybe ask her on a date. The only problem is I'm not sure if she has a boyfriend or not...What is a way to find this out.I want to talk to this girl, but I dont know if she has a boyfriend...How do I find out?
Try to sound casual in the conversation if you want to be sneaky about it, just ask her like: ';blah blah...so does your boyfriend come to cross country meets?'; Idk something along those lines so she tells you if she has or doesn't have a boyfriend. OR: just straight up ask her. BLUNTLY ask ';So, you have a boyfriend?';