bearing in mind that there are 60 minutes in 1 degree, and 60 seconds in 1 minute.
60°19'39"
so 39 seconds is really 39/60 minutes, or 0.65 minutes
so 19'39" is really 19.65'.
since there are 60 minutes in 1 degree, then 19.65' is really 19.65/60 degrees, or 0.3275°.
60°19'39" is then 60.3275°.