Area of a triangle formula

As promised, here is a formula for the area of a triangle that only depends on measurement of the sides of the triangle. We'll get into how those measurements are made in the next post. The derivation of this formula is really interesting, and I can supply it if someone asks.

Here's the triangle whose area we want to calculate, with sides a, b and c:

And here's that formula:

\[\displaystyle A\ =\ \sqrt{s(s-a)(s-b)(s-c)}, \displaystyle \ s\ =\ \frac{a+b+c}{2}\]

Cool, eh?!