1. (x2,y2)
(3,2)
(x1,y1)
(-4,-2)

2. (-5, -2) (4, 1)
x1 y1 x2 y2

3. Equation of a circle
(x – h)2 + (y – k)2 = r2
(h,k) is the center
r is the radius

4. Graphing a circle, give radius, center
(x – 3)2 + (y + 1)2 = 25
(h,k) is the center
(3,–1)
Plot center
Find radius
Plot points
Connect
r is the radius

5. Graphing a circle, give radius, center
(x + 2)2 + (y – 3)2 = 10
(h,k) is the center
(–2,3)
Plot center
Find radius
Plot points
Connect
r is the radius

6. Write equation given center and radius
(2,–4)
Center
Radius
(–1,2)
(x – 2)2 + (y –(– 4))2 =( )2
(x – (– 1))2 + (y – 2)2 = 32
(x – 2)2 + (y + 4)2 = 21
(x + 1)2 + (y – 2)2 = 9

7. Write equation of circle given picture
Center
Radius
(–1,2)
(x – (– 1))2 + (y – 2)2 = 32
(x + 1)2 + (y – 2)2 = 9

8. Write equation given center and point on circle.
Use distance formula to find radius
Then same as before.

9. HW #53: Pg 526: 5 – 8, 19 – 26, 27 – 30, 34 – 41, 45 (complete the square) [25 problems]