1. circle
Last Updated: October 11, 2005

2. Circle
The set of all co-planar points equidistant from a fixed point (center).
radius
Jeff Bivin -- LZHS

3. Circle
Equation: (x – h)2 + (y – k)2 = r2 r
(h, k)
Jeff Bivin -- LZHS

4. Circle r = r = 11 x – 3 = 0 x = 3 y – 5 = 0 y = 5 121 11 (3, 5) center
Jeff Bivin -- LZHS

5. Circle r = r = 9 x + 5 = 0 x = -5 y – 2 = 0 y = 2 81 9 (-5, 2) center
Jeff Bivin -- LZHS

6. Graph the following circle
9x2 + 36x + 9y2 - 18y - 10 = 89
9x2 + 36x + 9y2 - 18y =
9x2 + 36x + 9y2 - 18y = 99 9
(x2 + 4x + 22 ) + (y2 - 2y + (-1)2 ) =
(x + 2)2 + (y - 1)2 = 16
Jeff Bivin -- LZHS

7. Circle r = r = 4 x + 2 = 0 x = -2 y – 1 = 0 y = 1 16 4 (-2, 1) center
Jeff Bivin -- LZHS

8. Graph the following circle
4x2 + 24x + 4y2 + 32y + 13 = 157
4x2 + 24x + 4y2 + 32y =
4x2 + 24x + 4y2 + 32y = 144 4
(x2 + 6x + 32 ) + (y2 + 8y + 42 ) =
(x + 3)2 + (y + 4)2 = 61
Jeff Bivin -- LZHS

9. Circle r = x + 3 = 0 x = -3 y + 4 = 0 y = -4 61 61 (-3, -4) center
Jeff Bivin -- LZHS

10. Graph the following circle
5x2 - 80x + 5y2 + 20y - 34 = 106
5x2 - 80x + 5y2 + 20y =
5x2 - 80x + 5y2 + 20y = 140 5
(x2 - 16x + (-8)2 ) + (y2 + 4y + 22 ) =
(x - 8)2 + (y + 2)2 = 96
Jeff Bivin -- LZHS

11. Circle r = r = 4 6 x - 8 = 0 x = 8 y + 2 = 0 y = -2 96 4 6 (8, -2)
4 6
y + 2 = 0
(8, -2)
y = -2
center
(8, -2)
Jeff Bivin -- LZHS

12. Graph the following circle
2x2 + 10x + 2y2 + 8y + 4 = 25
2x2 + 10x + 2y2 + 8y =
2x2 + 10x + 2y2 + 8y = 21 2
(x2 + 5x ) + (y2 + 4y + 22 ) =
(x + )2 + (y + 2)2 =
Jeff Bivin -- LZHS

13. Circle r = r = x + = 0 x = y + 2 = 0 y = -2 center
Jeff Bivin -- LZHS