in 128.77°, there are 128° + 0.77°.
now, there are 60 minutes in 1 degree, and 60 seconds in 1 minute.
how many minutes in 0.77°? well, 60 * 0.77, or 46.2 minutes, which is really 46' + 0.2'
we know there are 60 seconds in 1 minute, so, how many seconds in 0.2'? well, 60 * 0.2, or 12 seconds.
so 128.77° is really 128° + 46' + 12", 128°46'12".
