1. Easy as “Pi” By Yamira Hart 6 th Grade Math Maven

2. There are circles all around you...

4. ? ? ? ? ? ? ? ? ? ? ? But have you ever considered how much there is to know about circles? Circles can be analyzed, labeled, and measured by their specific parts. It can be as easy as.... Pi.

5. Chord A chord is any line segment of a circle that connects two points on the circle.

6. Diameter The diameter is a chord that goes through the center of a circle.

7. Radius The radius is the segment or length of the segment from the center of a circle to any point on the circle. The radius is also half of the diameter!

8. Circumference The circumference is the perimeter of a circle. Remember, perimeter is the distance around a figure.

9. ? ? ? ? ? ? You can find the perimeter of a regular polygon by adding the lengths of the sides. But...a circle is NOT a polygon! So... how can you find the CIRCUMFERENCE of a circle???

10. The answer is... As easy as “pi”— with a little help from diameter or radius.

11. PI “Pi” is the ratio of the circumference of any circle to its diameter, approximately equal to 3.14.

12. Huh?

13. Simply stated... A ratio is a comparison of two numbers. In the case of circles, PI is derived by the ratio of the diameter to the circumference. Therefore...

14. Pi = ∏ If you take the diameter and stretch it around a circle, it will go around just over three times... 3.14 times, in fact!

15. A Special Formula C = ∏ D (Circumference = pi x diameter) or C = 2 ∏ r (Circumference = 2 x pi x radius) ( Since diameter = radius x 2!!!)

16. Try some pi! If the diameter of a circle is 6 inches and you want to know the circumference, multiply 6 in. (the D) by 3.14 (the ∏) to find C...

17. Ta-da!!! c = 3.14 x 6 in The circumference is approximately 18.84 in.!

18. A “rad” idea! Remember, you can also multiply the radius by 2, then multiply that number by pi to find a circumference. (C=2∏r)

19. So there you have it... If you use these vocabulary terms and formulas for working with circles, you’ll be right on target!

20. Or at the very least... You’ll be a