ΔE 30.6, loose: different enough that you should pick on purpose. Radiant Yellow is noticeably darker, much more saturated, warmer than Brass Balls.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 31). Radiant Yellow is noticeably darker, much more saturated, warmer than Brass Balls.
The same difference applies the other way round: Brass Balls is noticeably lighter, much more muted, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Brass Balls on the colour wheel See Radiant Yellow on the colour wheel
All matches: Brass Balls equivalents · Radiant Yellow equivalents