1. Mrs. Planavsky 4 th Grade

2.  Find the circumference of a circle  Find the measurement of a diameter of the circle

3.  The circumference of a circle is the distance around the circle.

4.  If you know the diameter of a circle, you can estimate its circumference!  You can find the EXACT measurement of the circumference of a circle by multiplying the diameter and pi (3.14).

5. A diameter is a chord that passes through the center of a circle.

6. CircleDiameterEstimated Circumference A2 cm B4 cm C7 cm D8 cm

7. 12 ft

8.  How do you know?

9. 10 cm

10.  How do you know?

11. 10 cm..

12.  How did you figure this one out?  What new information did you learn about finding the circumference?

13.  Half of the diameter is called the radius  So, 2 x radius= diameter