1. Bell Ringer 4-21-17 Write an example of each of the following:
1. Radius
2. Secant
3. Tangent
4. Chord
5. Diameter
6. Minor arc
7. Major arc
8. Central angle
9. Inscribed angle
10. Center

2. Arc Length
Friday April 21, 2017

3. Quick Definition Review
Chord: a segment whose endpoints lie on a circle A B AB

4. Quick Definition Review
Arc: an unbroken part of a circle

5. Quick Definition Review
Minor Arc: an arc that is less than half of a circle.
to name, use 2 points

6. Quick Definition Review
Major Arc: an arc that is more than half of a circle.
to name, use 3 points

7. Quick Definition Review
Central Angle: an angle whose vertex is at the center of a circle

8. Quick Definition Review
Inscribed Angle: an angle whose vertex is on a circle and whose sides are chords of the circle

9. Quick Definition Review
Tangent: a line, ray, or segment that intersects the circle in only one point (perpendicular)

10. Quick Definition Review
Secant: a line, ray, or segment that contains a chord

11. Arc Length
Arc Measure (yesterday) is in degrees. Arc Length is in units like cm, ft, and in.
Arc Length is a portion of the circumference just as an arc is a portion of the entire circle.
Everything is proportional when it comes to circles!
You need to know the central angle that intercepts your arc to set up your proportion.

12. Examples Find the arc length: 1. Radius 5 cm, central angle 50º
Find the circumference:
3. Central angle 55º, arc length 5.5 cm
4. Central angle 60º, arc length 3.82 m
Find the central angle:
5. Arc length 45 ft, radius 12 ft
6. Arc length 30in, radius 14 in

13. Classwork Homework Geometry book p. 686-688 #13-47 odd
Circumference and Arc Length

14. Exit Ticket
How does the proportion for arc length compare with the proportion for arc measure?
2. What is the difference between arc length and arc measure?