Richard Cline wrote:

In article ,
s wrote:

Yea but when you heat the wire, it gets thicker. That means
one side would move toward the center of the circle.

Let me offer another way to think about the problem:

Let's look just at the atoms that make up just the inner surface
of a ring. As the ring is heated, these atoms move farther from
each other. As they move farther from each other, the
circumference of this inner surface increases - and so, then,
must the diameter.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/solar.html