Chalkboard Geometry: Construct a Parallel Line

In this video, Chris demonstrates how to construct a parallel line through a given point using a circle arc template. He does this on a blackboard with chalk!

The specific construction problem he tackles is to draw a line parallel to a given line segment AB, passing through a point C that does not lie on AB. He proceeds with the construction as follows:

1. He starts by drawing a circle arc centred at C, intersecting AB at a point.
2. He draws a ray connecting C with the new point.
3. Using the circle arc template again, centred at the new point, he intersects the ray with the circle arc, creating another new point.
4. An arc is then formed from said point that intersects with AB to form a new point.
5. Another ray is then formed through the two previous points
6. A final point is formed from an arc centred at the previous point
7. Finally, he draws a line through C and the previous point, which is parallel to AB and passing through C.

And there you have it! With a circle arc template and some clever moves, Chris shows us how to make a line that's parallel to another and passes through a given point. And he did it all on a chalkboard!