Yes, I was very committed to HP48, wrote many programs and games back in the day, which can still be found.
I still use it daily, but as emulator on my Android.
here is how:
green shift -> units (#6)
hit next couple times to get to Angles menu (top row of buttons)
choose your deg Angle
enter number
hit degree menu at top
you can hit enter to make a duplicate
to convert a unit to another
purple shift -> desired unit. this takes the top stack and converts (replaces the stack) hence I like to make duplicate.