Prove that the two circles shown below are similar.

All circles are "similar" in a mathematical sense. If you can transform a shape but change all sides equally (for instance if you changed a rectangle by adding 2 to its length and 2 to its width) to the point where is matches another shape exactly, those shapes are similar.

Does that graph have a way to expand and move the circles? if so, take circle E and place its midpoint onto circle C's and then expand it till it matches circle C.

Let me know if I can further explain this.

I'm not sure but i think it's 1670km/h