# Circles in a circle

**Geometry**Level 4

Given that there are three identical circles with radius \(r\), each touches each other on their respective circumferences and they are all inscribed in a circle with radius \(R\). If the ratio of \(r\) to \(R\) can be expressed as

\[ \large \dfrac1{\frac a{\sqrt b} + c} \]

for positive integers \(a,b\) and \(c\) with \(b\) square-free, find the value of \(a+b+c\).