How to measure the percentage increase of radius?

I would like to measure the radius of the inner (black) shape at each point and the distance of the filled area from the centroid of the inner(black) shape in order to get the percentage increase in the radius of the original black shape. If it is not possible, at least I want the maximum increase in the radius

Any help please?

[Erik S.]

Can you provde a picture?

[Star Strider]

Please post the image you are referring to.

Use the green and brown ‘Picture’ icon, choose the image, and then upload it.