Section 10.6- Circles and Arcs
Essential Question: How is the length of a circle related to its angle measure?
2. Fill in the blanks with one of the following words.
Center
Diameter
Central Angle
Radius
What are arcs?

An arc is a __________ of a circle

Minor arc- ________________ than a _________________
o Name with its endpoints
o Use _____ letters to name it

Semicircle- __________ of a circle
o Use ______ letters to name it

Major arc- _______________ than a __________________
o Use _____ letters to name it

Follow the letters IN ORDER to help you identify the arc!
Example 1: Naming Arcs
a. Name 3 minor arcs of circle A.
b. What are the semicircles of A?
c. Name 3 major arcs of circle A that contain point Q.
a. Minor Arcs:
1. ______________
2. ______________
3. ______________
b. Semicircles:
1. ____________
2. ____________
c. Major Arcs with point Q:
1. ______________
2. ______________
3. ______________
Arc Measure

Measure of minor arc and major arc is ___________ to measure of its
____________________ _______________ _________________

Measure of semicircle is ________
Using Circle S below, find the following arcs.
Arc Addition Postulate
The measure of the arc formed by two _______________ arcs is the __________ of the
measures of the two arcs.
____________________
Example 2: Finding the Measure of Arcs
Example 3: Finding a Distance
Round your final answer to the nearest tenth.
Example 4: Finding Arc Length
a. What is the length of a semicircle with radius 1.3 m? Leave your answer in terms of 𝜋.
b. Find the indicated measure for
i. m∠FOG
.
ii. m JEG
Group Work:
1. Sample PARCC Question
2.
HW: p. 654-656 #12-26 evens, 29-35 odds, 47, 48