Orange You Glad vs Radiant Yellow

How close are they?

ΔE 25.7, loose: different enough that you should pick on purpose. Radiant Yellow is noticeably lighter, much more muted, cooler than Orange You Glad.

Can I use Radiant Yellow instead of Orange You Glad?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 26). Radiant Yellow is noticeably lighter, much more muted, cooler than Orange You Glad.

Can I use Orange You Glad instead of Radiant Yellow?

The same difference applies the other way round: Orange You Glad is noticeably darker, much more saturated, warmer.

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.