What is it that you want to teach? Many high schools don't teach business classes, although some do. If those you want to teach in do offer such classes, then being a business major would prepare you to teach there, so long as you also do student teaching and the other things your state requires to teach. I don't know how much demand there is for business teachers in the regions where you want to teach, so you'd need to check into that. It may be that there isn't too much, in which case you may want to do a secondary specialization (like special ed or bilingual or what have you) that would make you more employable, or learn to coach something in demand, etc.
If you are saying you want to teach math, then whether or not you can do so really depends on what state you plan to teach in, and in part on how many math classes you've taken. In some states, you can teach math even if you didn't major in it, so long as you've taken more than a certain number of college level undergraduate math classes. So, what are the rules re: teaching math in the states where you want to teach? Find out.
If you do want to teach math, have you thought of teaching it in elementary school, rather than in high school? In many states, in order to teach math at the elementary (and sometimes even early middle school) level, you don't need to major in math. You major in education. If this might interest you, look into it. It may be an alternative path into the profession you really wanted. And if your state allows people who majored in education to teach math at the middle school level, you'll get to teach algebra - in many states, the advanced students get to take algebra 1 in 8th grade. So this may be perfect.