Awood board 156 centimeters long is cut into three parts .the two longer parts are the same length and are 15 centimeters longer than the shortest part. how long are the three parts? how do you do this?

The everyone of two longer parts has 57 cm length and the shortest part has 42 cm length.
less 30cm from 156 and divide the remain amount of 126 into three parts. The answer will be 42 cm, then add 15,15 in longer parts.

The answers are 20,30,80,180,960,890,1230,4560. on the first row