keeping in mind that there are 60 minutes in 1 degree, and 60 seconds in 1 minute, and because there are 60 seconds in 1 minute, there are 60*60 seconds in 1 degree, or 3600.
48" (seconds) is then 48/60 or 0.8 minutes.
that means that 20' 48" is really 20.8'.
and since there are 60' in 1°, 20.8' is 20.8/60, about 0.3467°.
so 23° 20' 48" is then 23°20.8' or about 23.3467°