calculate dimensions of a shirt with openCV

I need a single python 3 file that will take path to the image as first argument. the images will be of a shirt but there will be a good coin placed at the center of the shirts. the dimensions of the coin will be given. Must use open cv to open the image, segment the gold coin, find radius of coin in pixels. then use the actual radius of coin to find the scale of pixel length to real length. then segment the shirt and calculate it's length and width. it should print the length and width on the console. To prove that you've read the requirements, discuss that you can do the task by saying "I can calculate dimensions of an object in an image ... " The budget of this task is $50. I'm a programmer too with experience in open cv so I know it is more than fair. please don't bid more than it.