1. Circles in the Coordinate Plane
9-7
Circles in the Coordinate Plane
Holt McDougal Geometry
Holt Geometry

2. Warm Up
Use the Distance Formula to find the distance, to the nearest tenth, between each pair of points.
A(6, 2) and D(–3, –2)
2. C(4, 5) and D(0, 2)

3. The equation of a circle is based on the Distance Formula and the fact that all points on a circle are equidistant from the center.

4. Write the equation of each circle.
J with center J (2, 2) and radius 4

5. Write the equation of each circle.
K that passes through J(6, 4) and has center K(1, –8)

6. Write the equation of each circle.
P with center P(0, –3) and radius 8

7. Write the equation of each circle.
Q that passes through (2, 3) and has center Q(2, –1)

8. Graph x2 + y2 = 16.
Graph x² + y² = 9.

9. Graph (x – 3)2 + (y + 4)2 = 9.
Graph (x – 3)2 + (y + 2)2 = 4.

10. Determine if the points are on, outside, or inside the circle.
Exterior:
Interior:
EX: (x-2)2 + (y-3)2 = 25.
a. (2,4) b. (-3,2) c. (-5,-1) d. (0,-2)

11. Lesson Quiz: Part I
Write the equation of each circle.
1. L with center L (–5, –6) and radius 9
2. D that passes through (–2, –1) and has center D(2, –4)

12. Lesson Quiz: Part II
Graph each equation.
3. x2 + y2 = 4
4. (x – 2)2 + (y + 4)2 = 16