There is a general formula to find the area of the inscribed circle. Investigate. [br](Hint: it's easier to see with Pythagorean triples such as 3-4-5, 5-12-13, 7-24-25, 8-15-17, 20-21-29 may help.)

Interestingly, the semi-perimeter, s appears in Heron's formula for the area of a triangle with sides of a, b and c:[br][math]A=\sqrt{s\left(s-a\right)\left(s-b\right)\left(s-c\right)}[/math]