# Grade 9 Circle Properties… on YouTube!

OK.  I gotta get me a TV.

I was working through some of the content for the Grade 9 curriculum and stumbled upon some YouTube videos that might be helpful.  The teacher who does the demonstrations is lovely, although the comments below her vids aren’t particularly kind.  If you show these to your students, consider using a full screen mode so they don’t see the nasty comments…. :o)

Try these instructional videos:

What’s a Tangent?

Arcs and Chords – problem solving to find the radius

Tangents and circles – problem solving

Inscribed angles problem-solving (quadrilaterals)

And for a lark, check out this “music video” that reviews the important parts of a circle (diameter, radius, pi, circumference, etc…).  Hey – I’ll try anything at this point!

If anyone out there has any gems to share in the way of interactive applets to demonstrate the circle properties (tangent to a circle, inscribed angles, bisected chord, angles in an inscribed quadrilateral) I’d be most grateful!

Carole

### One response

1. I would recommend using Geogebra. It is free mathematics software for teaching and learning. Here is the link:http://www.geogebra.org/cms/ There are many on-line tutorials explaining how to use the software and also how to create specific geometric constructions.

Teachers could construct circles that demonstrate the circle properties so students could explore and discover the angle relationships. More powerful, though, I think students could create their own circles to demonstrate their understanding of angle relationships as a summary of what they have learned in this particular unit.