1. Math Education Educational Technology EDU 529 Jun 30, 2003 David Bloom

2. Pi (  ) = 3.141592654..... radius A =  r 2 d = 2 r C =  d = 2  r d = 2 r Area Circumference Diameter Pi (  ) Perimeter Pi (  ) and the Circle C / d =  Circle Center Radius r = d / 2 diameter

3. Prior Knowledge About Rectangles Area = Length (Base) x Width (Height) = 3 x 1 = 3 square units Perimeter = Sum Length of the Outer Sides = 1 + 3 + 1 + 3 = 8 1 3

4. Vocabulary Circle –A circle is the set of points equidistant from a given point Circle

5. Vocabulary Circumference –The perimeter of a circle is called the circumference r O C Circumference C

6. Vocabulary Radius –The distance from the center of the circle to its perimeter is called the radius r O Radius r

7. Vocabulary Diameter –The diameter is the distance from one point on a circle to another point on a circle which passes through the center d Diameter d O

8. Vocabulary Pi –The number, Pi, denoted , is defined as the ratio of a circle’s circumference C to its diameter d d  = C / d C  = 3.141592654.....

9. Formula Circumference –The circumference of a circle can be calculated using the formula d C =  d C

10. Formula Area of a Circle –The area of a circle can be calculated using the formula r O Area =  r 2

11. Area of Circle – Step by Step

12. Application Circumference We use with formulas to find the circumference of circles. For example, if you are given the diameter of a circle, you can find the circumference by using this formula: Another formula for finding the circumference of a circle is:

13. Pie ‘r not round, Pie ‘r square (  r 2 )

14. Acknowledgements Music by Don McLean, American Pie, 1972