1. Graph and Write Equations of Circles
Notes 9.3 (Day 1)
Graph and Write Equations of Circles

2. Circles: Standard Form: Center point:
Today, both h and k are the opposite of what you think.
Radius:
Take the square root of the number on the right of the equation.
Before you do anything, put the equation into standard form.

3. Graph the circle, identify the radius.
Step 1: Find the center point. (h, k)
Step 2: Find the radius (don’t forget to take the square root)
Step 3: Graph the center point with an open dot (not a solution to the equation)
Step 4: Count r spaces in each direction and put points.
Step 5: Label radius.

4. Graph the circle, identify the radius.

5. Graph the circle, identify the radius.

6. Graph the circle, identify the radius.

7. Identify the radius and center of the circle.
Step 1: Solve for the constant (the number without the variable)
Step 2: Complete the square with the x value (make sure to add that number to both sides)
Step 3: Complete the square with the y value (make sure to add that number to both sides)
Step 4: Factor your two perfect square trinomials
Step 5: Identify the center (h, k) and the radius (take the square root of the right hand side)

8. Identify the radius and center of the circle.

9. Identify the radius and center of the circle.

10. Identify the radius and center of the circle.

11. Identify the radius and center of the circle.

12. Homework:
Graphing and Properties of Circles WS