What is the radius of the circle inscribed in triangle $ABC$ if $AB = 15,$ $AC = 41,$ and $BC = 52$?
A = rs
semiperimeter = s = (15 + 41 + 52)/2 = 54
area = A = √s(s−a)(s−b)(s−c)=√(54)(2)(39)(13)=234
radius = r = As=23454=133
+1223 
