What is the ratio of the radii of the 3rd orbits of `He^(+)` and `Li^(2+)`?

Explanation

Here n is constant and its value is 3. Z of `He^(+)=2 ,Z` of `Li^(2+)=3`
`(r_(1))/(r_(2))=(Z_(2))/(Z_(1))=(3)/(2) or 3:2`