Circles squares and triangles are everywhere.  We know how to measure the distance around them, their perimeter, and the space inside them, their area.  These three figures are fundamental to the study of geometry and occur everywhere in mathematics, physics, chemistry and all other physical sciences.  Learn them well.  They will be with you your entire life.

Lets start our study of these basic figures with a look at circles.  Circles are very important figures which are basic in all further study of science.  Here is a web site about  CIRCLES.  At this site you will find the definition of a circle, information about how circles and trigonometry are related and formulas for the area and circumference of a circle.  Take your time and explore this useful web site.  Take notes and jot down questions if you have them.

Now that you understand circles, let's have a look at squares.  One problem which gave the ancients great difficulty was trying to find the radius of a circle having the same area as a given square.  It can't be done exactly.  Any idea why?  Hint, it has to do with the number PI.