| A | B |
|---|
| A 2 dimensional flat figure in which all points are equidistant from a given point | circle |
| The length of the radius of a circle is | the distance from the center to any point on the circle |
| A line segment that passes through the center of the circle and has endpoints on the circle | diameter |
| One half of the diameter | the radius |
| Distance around the circle | circumference |
| Definition of Pi | C/d |
| The formula for circumference | C = Pi X d |
| A semi-circle is | half a circle |
| The approximation for Pi used in our book | 3.14 |
| The formula for the area of a circle | (Pi)(r squared) |
