1. ## Contact Point?

If a circle rolling, where the point N will make contact with the line? Thank you

2. ## Re: Contact Point?

Hey geomathry.

Hint: What is the formula for the arc-length of the portion of the circle that goes from start point to point N?

3. ## Re: Contact Point?

Originally Posted by chiro
Hey geomathry.

Hint: What is the formula for the arc-length of the portion of the circle that goes from start point to point N?

But that not the answer I would like to have.

I would like to know the construction where the length of arc and the length of line are equal.

4. ## Re: Contact Point?

A geometric "construction"? chiro told you how to find the distance from the current point of contact to the point where N contacts the surface. That was what your orginal post asked. If you want a construction to give that point, put one point of compasses at the current point of contact, the other at N and strike an arc to cross the line.

5. ## Re: Contact Point?

Originally Posted by HallsofIvy
A geometric "construction"? chiro told you how to find the distance from the current point of contact to the point where N contacts the surface. That was what your orginal post asked. If you want a construction to give that point, put one point of compasses at the current point of contact, the other at N and strike an arc to cross the line.
You told me to put one point of compasses at the current point of contact but the current point of contact is unknown and the one is being looking for.

Confuse.