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

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

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

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

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

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

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

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

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