Homeschool Math Blog

I got inspired by the blogpost Art School | Geometric Design with Islamic Art where Deborah shows how to make a neat flower design with seven circles , using a compass, and then coloring it using 2, 3, or 4 colors (or however many of your own). I think it ties in neatly with mathematics, and lets students practice drawing circles with a compass.  My girls loved the art/math project. Here are pictures they made: Here are step-by-step instructions for the flower design: 1.  Draw a line and a circle so that the circle's center point is on the line. Then mark the points where this circle intersects the line. 2. Use those points as center points, and draw two more circles. The radius is the same all the time, so make sure you don't change it on your compass!We used 5 cm as the radius, and that made the whole design fit neatly on a regular letter size paper. 3. Now note the two points marked in the picture. They will be used as center points in the next...

Today I had the opportunity to solve a real math problem involving a circle and a chord of known length in it. I had to find the radius . It wasn't a textbook problem or a puzzle on some website, but a math problem I needed to solve for my own needs. For a tiny while I thought I could find the answer online, but I didn't, so I'm writing it out in case someone else needs it -- they should be able to find this solution by searching the Internet. I wanted to make a kind of " moon-sliver shapes" in CorelDraw, to use as watermarks in my new books. I have the height and the width of the "sliver". Here's the problem mathematically: I have a chord of a circle, 17 mm in length in my example, and the other distance marked in the image is 5 mm. I need to find the radius of the circle, AND the angle measure of the arc of the circle that makes the sliver's rounded part. At first, like I said, I searched around if there was some theorem or ...

This was sent to me... I thought it was a very cute, melodic song about learning circle-related terminology such as radius, diameter, and circumference, and the two formulas with Pi (area formula and circumference formula): Here's a direct link in case you want to spread it around: http://www.youtube.com/watch?v=-z4SUypJZxo This is done by Dave Mitchell who also has a website Arithmecode.com .