Two point masses each equal to $1$ kg attract one another with force of $10^{-10}N$. The distance between the two point masses is $(G=6.6\times 10^{-11}MKS$ units$)$

According to newton's Gravitational Law
$F_g=\frac{G{M}_1{M}_2}{r^2}$ here $F_g=10^{-10}$ Newton,
$m_1=m_2=1$kg,
$G=6.6\times 10^{-11}$
So $r^2=\frac{G{M}_1{M}_2}{F_g}=\frac{6.6\times 10^{-11}\times 1\times 1}{10^{-10}}=0.66$
or $r=0.8125$ metre $=81.25cm=80cm$