Look on the file exchange. There are tools to compute triangle areas. But really, you need to make some effort, rather than someone just giving you the answer.
This is your project, not ours. Even if you look for code, at least you will need to learn something about that code, how to use it. You will gain in doing that work too. But if we give you code, you learn only how to plead for others to do your work for you. And if your response would be that you don't have the time, then you will learn how to manage your time better in the future.
