There are 3 tangent circumferences
inscribed in an isosceles right triangle
Two of these circumferences have
radius R and are tangent to the
hypotenuse and to the two cathetus.
The smaller circumference has
radius r and is tangent to the two
cathetus. How can I find the radius
of the smaller circumference as a
function of R?
(I want a tip on how to solve the
problem).