Heron's Formula

Heron's formula: √(s*(s-a)*(s-b)*(s-c)) where s is (a+b+c)/2. From my trigonometry class I learned that Heron's formula wasn't hard. Just tedious and time consuming. And I thought there should be an app for that. So in about an hour I wrote one. And here it is, prettied up a bit of course. Now with the ability to control the precision of the answer. Choose up to 8 numbers behind the decimal point. *Note: it does not work with just any numbers. Because not all combinations of numbers create a triangle. And it does not round the final decimal place shown. But it should still work for any homework problems :)