how do you find area using trigonometry ?
Let me expand on what Melody said.......what if we only know the sides of a triangle but we don't know any of the angles??
Well, we could use the law of cosines to find any of the included angles and then use the formula that Melody gave - a two step process.
Here's another way.....it's known as Heron's (or Hero's) formula
First....add all the sides of the triangle and divide by 2.....this is known as the semi-perimeter (S)
Then, multiply S*(S-A)*(S-B)*(S-C) where A, B, C are the side lengths of the triangle
Now take the square root of the product you just obtained, and that's the area.
The beauty of this "formula" is that there's really no trig involved at all!!
Your choice, though!!