Nuclear radius of the gold isotope $_{\tau g} A u^{197}=R_{A u}$

Nuclear radius of the silver isotope $_{47} A g^{107}=R_{4 g}$

Mass number of gold, $A_{A u}=197$

Mass number of silver, $A_{A g}=107$

The ratio of the radii of the two nuclei is related with their mass numbers as

$\left( R _{ A w } / R _{ A g }\right)=\left( A _{ A u } / A _{ A g }\right)^{1 / 3}=1.2256$

Hence, the ratio of the nuclear radii of the gold and silver isotopes is about $1.23$