An angle of 1º can be divided into 60 equal parts.
Each of these parts is known as 1 minute (1').
So 60' = 1º
An angle of 1' can be divided into 60 equal parts.
Each of these parts is known as 1 second (1").
So 60" = 1' and 3600" = 1º
Example
Convert 13.49º into an angle in degrees, minutes and seconds.
Answer
Just look at the part after the decimal point i.e. 0.49º
Use a calculator to work out 0.49 x 60 = 29.4
13.49º = 13º 29.4'
Now again look at the part after the decimal point in 29.4' i.e. 0.4'
Use a calculator to work out 0.4 x 60 = 24"
So 13.49º = 13º 29' 24"