1. Warm Up
Identify the parts of the circle
10 minutes
End

2. Unit 6 Day 2
Circle Relationships

3. Angle Properties Angle formed by a Tangent and Radius
Central Angle of a Circle
Angles formed by 3 points on a circle (Inscribed)
Angles formed by secants or tangents

4. Can you draw a radius to each point of tangency
Can you draw a radius to each point of tangency? What do you notice about the angle formed by the radius and tangent line in each picture?

5. Radius and Tangent
A radius and a tangent line meet at a 90º angle.

6. On the circle Center Central Angle Inscribed Angle Outside the circle
Picture 1
Picture 2
Picture 3
Where is vertex?
Name of Angle
Formula:
Center
On the circle
Outside the circle
Central Angle
Inscribed Angle
***

9. Finding Length and Area
Angles can be measured by DEGREES or RADIANS *Think centimeters and inches A full trip around a Circle is 360 degrees OR 2π radians

10. Converting between Degrees and Radians
To Convert from degree to radian PART(degree) Whole (360) To Convert from radians to degree PART(radian) Whole (2π)
X 2π
X 360

11. Examples
Convert the following.
150 degrees
45 degrees
3π/2
π/6

12. Arc Length Formulas
We have two formulas to find arc length. Decided which to use base off of the information we are given: Degrees: Radians:

13. Area of a Sector
Again, we have two different formulas to find the area of a sector. Degrees: Radians: