Inside triangle
there are three circles
each of which is tangent to two sides of the triangle and to its incircle
. The radii of
are
, and
. Determine the radius of
%V0
Inside triangle $ABC$ there are three circles $k_1, k_2, k_3$ each of which is tangent to two sides of the triangle and to its incircle $k$. The radii of $k_1, k_2, k_3$ are $1, 4$, and $9$. Determine the radius of $k.$
Školjka