1. Lesson 10-3: Circles

2. Equation of a circle (x – h)2 + (y – k)2 = r2
Circle: the set of all points in a plane that are equidistant from a given point in the plane
Center: the point that all points in a circle are equidistant from
Equation of a circle (x – h)2 + (y – k)2 = r2
h = x value of center
k = y value of center
r = radius length .

3. Graph (not in packet)
Center (8, -3) r=6

4. Identify the center and radius for each circle given
Identify the center and radius for each circle given. Then graph the circle.
Center (7, -3) passes through the origin

5. Center (-2, 8) and tangent to y=4

6. (x-3)2 + y2 = 9

7. Write the equation in standard form then graph.
x2 + y2 – 4x + 8y – 5 = 0

8. Write the equation in standard form then graph.
x2 + y2 + 4x - 10y – 7 = 0

9. Write the equation for the circle described.
Center (-1,-5) radius 2 units
Endpoints of a diameter at
(-4, 1) and (4, -5)

10. A plan for a park puts the center of a circular pond of radius 0
A plan for a park puts the center of a circular pond of radius 0.6mi, 2.5mi east and 3.8mi south of the park headquarters. Use the headquarters as the origin and write an equation to represent the situation.