Below is a piece of Kulliwari Art created by Michael J. Connolly, titled The Rainbow Serpent. Calculate the area of the image covered by the snake. The dimensions of the canvas from the outer edge of the grey border is 80cm by 100cm. It is very important that you show clear working and justification for your answer.

Please tell me what to do and how to do it.
If you give an answer please provide a detailed justification.
Lots of points in it for you! ;)