This Shape is made using three semicircles. The smaller semicircles have diameters of 10cm.

Calculate the shaded area.
Take π to be 3.142 and write down all the digits given by the calculator.

I already know the answer, but dont understand how it concluded to it, so please only answer if you'll provide working out. Here's a picture of the shape, it would be great if someone can mark down where the three semi circles are on an easy platfrom such like paint since i can't seem to point them out. Thank you, giving brainliest to the first correct answer :)))