Question

1) Please Show Me How To Convert (-3)radian to Degree-Minutes-Second ?

Answer 1

`-171° 53'13.2`''

Explanation:

I'm assuming that for degrees and minutes you want integer values.
In general `pi` radians are `180` degrees.
so `-3` radians are `-3*180/pi` degrees or `-171.887339°`

-171 is the closest integer so you have that many degrees.
But, you can't forget about the numbers after the decimal

There are 60 minutes of arc per degree, so
`.887339°*60` = `53.24034` minutes of arc.
Again, we take the closest integer lower than our number, so `53` minutes. This is written as `-171°53'` and read as negative (or minus) 171 degrees, 53 minutes.

Just like in time, there are 60 seconds in a minute.
We have `0.24034` minutes we don't have in our incomplete answer, so we again multiply by `60`.
`60*0.24034` = `13.2` seconds of arc.
We write the complete answer as `-171° 53'13.2`'' and is read as negative (or minus) 171 degrees 53 minutes 13.2 seconds (saying of arc is optional)