1. 12.5 Circles in the Coordinate Plane
Chapter 12: Circles
12.5
Circles in the Coordinate Plane

2. Conic Sections
These are cross sections of a cone:

3. Theorem 12-13
An equation of a circle with center (h,k) and radius r is:
This is called the Standard Form of an Equation of a Circle.

4. Example 1
Write the standard equation of a circle with center (5,-2) and radius 7.

5. Example 2
Write the standard equation of a circle with center (1,-3) that passes through the point (2,2).

6. Example 2a
Write the standard equation of the circle with center (2,3) that passes through the point (-1,1).

7. Example 3
Find the center and radius of the circle with equation (x – 7)2 + (y + 2)2 = 64. Then graph the circle.

8. Example 3a
Find the center and radius of the circle with the equation (x – 2)2 + (y – 3)2 = Then graph the circle.

9. Example 3b
Find the center and radius of the circle with equation (x + 4)2 + (y – 1)2 = 25. Then graph the circle.

10. Challenge
The point (-1,4) is on a circle with center (5,-2). Find the standard equation and diameter of the circle. Leave your answer in simplest radical form.

11. Homework
P. 697
2 – 20 even, 28 – 38 even