Circles... Lowest Form of Geometric Life?
Somewhere out there I'm sure there's a guy whose job is just to come up with crazy sounding names for all the shapes in the geometry zoo. Worse than the guy who names bacteria. But I suppose, better that than working out all the equations needed to compute key measurements for all those mangy beasts.
Fortunately, we're starting near the bottom of the geometric food chain. After all, what's less complex than a shape with exactly one side? Of course, that's our friend, the perfect circle... The single-celled organism of math. Circles are special in that given one dimension, you can determine all sorts of interesting facts. Got a radius? You're a few multiplications away from a diameter, area and circumference. And if your basic algebra kung-fu is strong, you can go from area to diameter to radius to circumference just as easily.
Given all the interesting tricks you can do with circles, it's no surprise how big a role simple circle geometry plays when you start getting into trigonometry. Which is all the more reason for getting the basics down early, and hence the healthy collection of circle geometry worksheets at the links below. Enjoy!