Solution :
Inradius Formula (r) = \(\Delta\over s\)
Where r = radius of the circle inscribed in a given triangle
\(\Delta\) = area of the given triangle
\(\Delta\) = \(\sqrt{s(s – a)(s – b)(s – c)}\)
s = half perimeter of the given triangle
s = \(a + b + c\over 2\) for all a, b c are the sides of a given triangle.