1. 10.1 Circle and Circumference Then: You identified and used parts of parallelograms Now: 1. Identify and use parts of circles. 2. Solve problems involving the circumference of a circle. http://planet-six-forum.838590.n3.nabble.com/file/n2648906/maxair_01.jpg

2. Parts of a Circle To name a circle, use the center point and the symbol

3. Example 1: Identify Segments in a Circle A. Name the circle and identify a radius.

4. Example 1: B. Identify a chord and a diameter of the circle.

5. Example 1: C. Name the circle and identify a radius.

6. Radius and Diameter *By definition, all radii are of a circle are congruent. *Since a diameters is made of 2 radii, all diameters of a circle are also congruent. http://hotmath.com/hotmath_help/topics/circle/circle-basic.gif

7. Example 2: Find Radius and Diameter A. If RT = 21 cm, what is the length of QV?

8. Example 2: B. If RV = 14.5 cm, what is the length of SQ?

9. Circle Pairs

10. Intersection of Circles One point of intersectionTwo points of intersection http://jwilson.coe.uga.edu/EMAT6680Fa06/Sexton/Assignment%206/Tang ents%20to%20Circles_files/image013.png

11. Example 3: Find Measure of Intersecting Circles A. The diameter of circle X is 22 units, and the diameter of circle Y is 16 units, and WZ is 5 units. Find XY.

12. Example 3: B. The diameters of circles D, B, and A are 4 inches, 9 inches and 18 inches respectively. Find AC..

13. Circumference *Distance around a circle. *Exact answer: write the  symbol and don’t calculate the decimal value. http://scienceforkids.kidipede.com/math/geometry/pictures/radius.gif

14. Example 4: Find Circumference CROP CIRCLES A series of crop circles was discovered in Alberta, Canada, on September 4, 1999. The largest of the three circles had a radius of 30 feet. Find its circumference. http://2012theyear.org/wp-content/themes/city- desk/timthumb.php?src=http%3A%2F%2F2012theyear.org%2Fwp- content%2Fuploads%2F2012%2F02%2FFlower-of-lifce-crop- circle.jpg&q=90&w=450&h=300&zc=1

15. Example 5: Find Diameter and Radius Find the diameter and the radius of a circle to the nearest hundredth if the circumference of the circle is 65.4 feet.

16. Inscribed polygon/Circumscribed circle *  ABC is inscribed in Circle D and * Circle D is circumscribed about  ABC.

17. Example 6: Find the Exact Value A. Find the exact circumference of Circle K.

18. Example 6: B. Find the exact circumference of the circles. 1. 2.

19. 10.1 Assignment Pages 701-703 #10-21 all, 22-44 evens