Title: Theorem 6.19
1Theorem 6.19
pd
The circumference C of a circle is C ____ or
C _____, where d is the diameter of the
circle and r is the radius of the circle.
2pr
pd
2pr
2Use the formula for circumference
Example 1
Find the indicated measure.
- Circumference of a circle with radius 11 meters
- Radius of a circle with circumference 18 yards
Solution
3Checkpoint. Complete the following exercise.
- Find the circumference of a circle with the
diameter 23 inches.
4Theorem 6.20
In a circle, the ratio of the length of a given
arc to the circumference is equal to the ratio of
the measure of the arc to 360o.
5Find and use arc lengths
Example 2
Find the indicated measure.
- Arc length of AB
6Find and use arc lengths
Example 2
Find the indicated measure.
Write equation.
Substitute.
Multiply each side by _____.
Use a calculator.
7Checkpoint. Find the indicated measure.
- Arc length of AB
8Checkpoint. Find the indicated measure.
9Pg. 236, 6.7 2-24 even