How would you know if girls in high school are attracted to you?

[The Siz]

I am pretty muscular i have been told I looked like Bruce Wayne/Batman many times. I Have been asked out by some girls before. many girls come up to me and say im attractive, but there are 2 girls that i like but cant tell if they like me or not. Like this girl in my math class today(Call her Girl 1)(she has a boyfriend though so im not too into her though) is taking off her coat showing off her attractive body and attire and also keeps looking at me during class too. im like "what? why does she keep looking at me? doesnt She have a Boyfriend?" I mean we talked sometimes but not often. I sometimes day-dream about her and she is really cool and pretty, but i dont know what is going on.I would litterally do almost anything for "Girl number 1". im just wondering if she is trying to tell me something. I would definently go out with her if she was single.

Girl Number 2" i have more interest at the moment in because she is single. I have had this girl in the past 2 years. she has been in on of my classes in the last two years(but none this year). I also Have been on the track team with Her. she is really pretty and physically fit(I definently day dream about her). we have talked once before(she initiated the conversation of something about me) but that is it. we walk past each other multiple times a day but never say anything. whenever we pass each other we make eye contact for a moment and break and one time in study hall she came to my class room to finish a test or something, after the test she had to stay in the room(school policy) and she kept looking at me while im trying to set up my NFL Fantasy Team. when passing each other in the hallway, we dont really get close when we walk by each other but today when i was walking to my class she got super close to me and without making eye contact walked passed me. this through me off.

I really like both of these girls but dont know if they are attracted to me or not. can you give me some signs that might show me if they like me or not(For both Girls 1 and 2)? and also how can I go and talk to them with out looking stupid? IN DEPTH ANSWERS WILL HELP ME AND WILL MOST LIKELY RECEIVE THE POINTS!!!!!!!!!!