1. Graph and Write Equations of Circles
Notes 9.3 (Day 2)
Graph and Write Equations of Circles

2. Write the standard form of the equation of the circle with the given radius and whose center is the origin.
r = 10
r = 4

3. Write the equation of a circle given a center point and a point on the circle.
Step 1: Find the distance between the center point and the given point. (use the distance formula)
Step 2: Insert the centerpoint and radius length into the given equation
Step 3: Simplify

4. Write the standard form of the equation of the circle that passes through the given point and whose center is the origin.

5. Write the standard form of the equation of the circle that passes through the given point and whose center is the origin.

6. Write the standard form of the equation of the circle that passes through the given point and whose center is the origin.

7. Tangent Line: -Crosses a circle at exactly one point
-Is perpendicular to a radius at that point

8. Write the equation of a line tangent to a circle at the given point.
Step 1: Find the slope of the segment connecting the center point and given point of the circle.
Step 2: Take the opposite reciprocal of the slope (perp. Lines have opp. Reciprocal slopes)
Step 3: Plug in the point and slope into the equation of a line
Step 4: Solve for the (b) value.
Step 5: write the equation of the line.

9. Write the equation of a line tangent to the circle at the given point.

10. Write the equation of a line tangent to the circle at the given point.

11. Write the equation of a line tangent to the circle at the given point.

12. Homework:
P , 31-42, 53-58