1. Geometry 11-5 Circles in the Coordinate Plane

2. Equation Exploration Get your supplies Graph Paper Compass?

3. Equation Exploration 1.Make a table of values to graph the equation x 2 +y 2 =4 2.Complete enough of your table of values to complete the graph

4. Equation Exploration You should have graphed a complete circle. What is the radius of the circle? Re-write the equation of the circle using the radius instead of a number.

5. Equation Exploration Make another table of values to graph the equation (x-3) 2 +(y-3) 2 =9 Complete enough of your table of values to complete the graph

6. Equation Exploration (x-3) 2 +(y-3) 2 =9 What are the coordinates of the center of the circle? (3,3)

7. Equation Exploration (x-3) 2 +(y-3) 2 =9 What is the radius of the circle? 3

8. Equation Exploration (x+2) 2 +(y-4) 2 =16 What are the coordinates of the center of the above circle equation? (-2,4)

9. Equation Exploration What is the radius of a circle defined by the following equation? x 2 +y 2 =49 The radius is 7

10. Standard Equation of a Circle The standard equation for a circle is written in the following form (x-h) 2 + (y-k) 2 = r 2 The radius of the circle is r The center of the circle is (h,k)

11. Example

16. Sample Problems Circles in the Coordinate Plane

17. Center = (0,4) Radius = 3

18. Center = (5,0) Radius = 4

19. Center = (-1,1) Radius = 2

20. Center = (-4,2) Radius = 5

21. (x) 2 +(y) 2 =9

22. (x) 2 +(y-2) 2 =4

23. (x-1) 2 +(y-1) 2 =1

24. (x) 2 +(y-1) 2 =4

25. (x-3) 2 +(y-3) 2 =16

26. Practice

34. Interior On Exterior On Interior

35. Homework Pages 617 – 619 2, 6, 8, 10, 12, 16, 18, 28, 30, 32, 34, 36