1. 7-3 Circles p. 424

2. Formulas for circles

3. Example 1 A dog is tied in a yard using a 15-foot leash. The leash is anchored 6 feet south and 9 feet west of the dog’s food and water bowls. Assuming the bowls are at the origin, write an equation for the set of points at which the dog will be at the maximum length of the leash. Then draw the graph.

4. Example 3 Write an equation of the circle that has its center at (2, -4) and is tangent to the x-axis. Tangent is defined as a line that intersects the circle in exactly one point.

5. Example 4 Write an equation of a circle if the endpoints of a diameter are at (1, 8) and ( 1, -6).