P is a point on the circumference of a circle radius r which rolls,
without slipping, inside a circle of radius 2r. What is the locus
The coke machine in college takes 50 pence pieces. It also takes a certain foreign coin of traditional design...
What happens to the perimeter of triangle ABC as the two smaller
circles change size and roll around inside the bigger circle?
A solution based on the one from Richard is
given below. I was not able to use Richard's original diagram but
hope the one submitted is sufficient:
A little more from Andrei - many thanks: