why mostly a guy has to approach a girl?

Girls are scared. They just don't show it. You have that fragile ego. Girls have fragile self-esteem. And probably peer pressure. You're still in high school (or college), I am assuming. Girls can be harsh critics. That's another thing that the NICE ones have to watch for. Don't worry too much. When you get older, you'll find that there are more women doing the asking.

That is all very nice in theory. But, when a girl approaches a guy in this way, mostly he runs away like a scared rabbit. So all a girl can do is try to let him know she likes him, eye contact, smile, say hello, and leave the rest up to him. Sometimes it is quite annoying because, guys don't take hints very well. So what else can a girl do?

Guys are dominant, even though we're all supposedly equal, the guys are the ones who should start first. Ever heard of chivalry? =_=;

This is because from the begining of time- man has courted women. But times have changed...if you are lucky enough to be approached by a girl...but until then....

its part tradition, so psychologically girls will wait, plus girls are way more insecure..., i know very few girls who go up to guys, and the ones who do are very confident females...

It should be the other way around.