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 42º 14' 32" into an angle in decimal format to 2 decimal places.

Answer

14' = 14/60 degrees.

32" = 32/3600 degrees.

Use a calculator to work out:

42 + 14 ÷ 60 + 32 ÷ 3600

So 42º 14' 32" = 42.24222222º... = 42.24º (to 2 dp)