a
\({m_1}{r_1}\,\, = \,\,{m_2}{r_2}\) અને \({r_1}\, + \,\,{r_2}\, = \,\,r\,\)

\(\, \Rightarrow \,\,{r_1}\,\, = \,\,\,\frac{{{m_2}r}}{{{m_1} + {m_2}}}\,,\,\,{r_2}\,\, = \,\,\frac{{{m_1}r}}{{{m_1} + {m_2}}}\)

જડત્વ ની ચક્માત્રા \(\,\,I\,\, = \,\,{m_1}\,r_1^2\,\, + \,\,{m_2}r_2^2\,\, = \,\,{m_1}\,\,{\left( {\frac{{{m_2}r}}{{{m_1} + {m_2}}}} \right)^2}\, + \,\,{m_2}\,\,{\left( {\frac{{{m_1}r}}{{{m_1} + {m_2}}}} \right)^2}\,\)

\( = \,\,\left( {\frac{{{m_1}{m_2}}}{{{m_1} + {m_2}}}} \right)\,\,{r^2}\)