1. 11-2 Arcs and Chords Warm Up Lesson Presentation Lesson Quiz
Holt Geometry

2. Objectives Apply properties of arcs.
Find the Circumference of Circles.

3. Vocabulary central angle semicircle arc adjacent arcs
minor arc congruent arcs
major arc

4. Note 70
A central angle is an angle whose vertex is the center of a circle. An arc is an unbroken part of a circle consisting of two points called the endpoints and all the points on the circle between them.

6. Example 1: Data Application
The circle graph shows the types of grass planted in the yards of one neighborhood. Find mKLF.

7. Check It Out! Example 1
Use the graph to find each of the following.
a. mFMC
b. mAHB
c. mEMD

8. Adjacent arcs are arcs of the same circle that intersect at exactly one point. RS and ST are adjacent arcs.

9. Example 2: Using the Arc Addition Postulate
Find mBD.

10. Check It Out! Example 2a
Find each measure.
mJKL

11. Check It Out! Example 2b
Find each measure.
mLJN

12. Within a circle or congruent circles, congruent arcs are two arcs that have the same measure. In the figure ST  UV.

13. The Circumference of a circle can be found by using on of the formulas:
C = 2pr or C = pd

14. Find the circumference of circle P if JM = 12cm

15. The length of an arc is a fraction of the circumference of the circle.

16. Example 4A: Finding Arc Length
Find each arc length. Give answers in terms of . FG

17. Example 4B: Finding Arc Length
Find each arc length. Give answers in terms of .
an arc with measure 62 in a circle with radius 2 m

18. Check It Out! Example 4a
Find each arc length. Give your answer in terms of . GH

19. Lesson Quiz: Part I
1. The circle graph shows the types of cuisine available in a city. Find mTRQ.
158.4

20. Lesson Quiz: Part III
Find each measure. Give answers in terms of 
2. Length of NP
3. Circumference of circle Q
4. Measure of LMP