Convertion of Decimal Degree to Degree Minutes Seconds (DMS) & Degree Minutes Seconds (DMS) to Decimal Degree

How to convert decimal degrees to degrees,minutes,seconds (DD to DMS)
 
One degree (º) is equal to 60 minutes (') and equal to 3600 seconds ("):
1º = 60' = 3600"

The integer degrees (d) are equal to the integer part of the decimal degrees (dd):
d = integer(dd)
 
The minutes (m) are equal to the integer part of the decimal degrees (dd) minus integer degrees (d) times 60:
m = integer((dd - d) × 60)
 
The seconds (s) are equal to the decimal degrees (dd) minus integer degrees (d) minus minutes (m) divided by 60 times 3600:
s = (dd - d - m/60) × 3600
 
Example: 
 
Convert 30.263888889º angle to degrees,minutes,seconds:
d = integer(30.263888889º) = 30º
m = integer((dd - d) × 60) = 15'
s = (dd - d - m/60) × 3600 = 50"
So
30.263888889º = 30º 15' 50"

How to convert degrees,minutes,seconds to decimal degrees (DMS to DD)
 
One degree is equal to 60 minutes and equal to 3600 seconds:
1º = 60' = 3600"

One minute is equal to 1/60 degrees:
1' = (1/60)º = 0.01666667º

One second is equal to 1/3600 degrees:
1" = (1/3600)º = 2.77778e-4º = 0.000277778º

For angle with d integer degrees m minutes and s seconds:
dº m' s"

The decimal degrees dd is equal to:
dd = d + m/60 + s/3600

Example:
 
Convert 30 degrees 15 minutes and 50 seconds angle to decimal degrees:
30º 15' 50"
The decimal degrees dd is equal to:
dd = d + m/60 + s/3600 = 30º + 15'/60 + 50"/3600 = 30.263888889º