Two Coins Math Problem solution

I hope you enjoyed this one!

[БранимирМилошевић]

oh, it's an equal contribution of orbital rotation and linear-travel rotation... so the rotation of the outer coin is always 2X the degree-value of the point where it's touching the inner coin

[idiocide]

I solved it in my head. Pure mental image. I feel proud.

[Horinius]

I think the answer could even be better explained by using color chalks, eg the first half of the coin's circumference (and of the straight line as well) is drawn in red while the second half in green. This could help people imagine :)

[tobse]

I was rly confused because a full turn is such an obvious answer. N1

[nbfalastine]

can i know where r u from plz enswer

[TyYann]

Check my channel, everything is there...

[Zitusssss]

i thought it's something like pi * pi ^^