1. 11.4 Arc Lengths March 20, 2013
Bellwork
Figure I ~ Figure II. Find the ratio of the perimeters and the
ratio of the areas. Then find the unknown area.
Ratio of perimeters: 4:3;
ratio of areas: 16:9;
Unknown Area :33.75 ft 2
2. Rectangle I ~ Rectangle II.
In Rectangle I, the length is 20 feet & the perimeter is 64 feet.
In Rectangle II, the width is 8 yards.
Find the ratio of the area of Rectangle I to the area of Rectangle II.
144 : 576
1 : 4
Mar 7­10:19 AM
HW pg. 749 #4­26 evens 1

2. 11.4 Arc Lengths March 20, 2013
11.4 Circumference & Arc Length
Circumference of a Circle:
C = 2πr (Twinkle­twinkle)
The circumference of a circle is 28 What is the area of the circle?
π.
Mar 7­10:29 AM
HW pg. 749 #4­26 evens 2

3. 11.4 Arc Lengths March 20, 2013
Arc Length: fraction of a circle's circumference
xo where x = the arc measure
360 *circumference
D
o
M
0
yd
28
6.5
C
C B
4i
n
o
60
A N
Length AB = ____ Length minor arc
MN = ____
Mar 7­11:51 AM
HW pg. 749 #4­26 evens 3

4. 11.4 Arc Lengths March 20, 2013
M
cm
22
P
Q
N
0
50 Arc QN = 60 o
Find the length of arc NM.
Q M
diameter = 9 ft
Length of QM = _______
The length of AB is 6 π. Find the radius.
120 o
A
r
B
Mar 7­12:03 PM
HW pg. 749 #4­26 evens 4

5. 11.4 Arc Lengths March 20, 2013
Mar 21­7:30 AM
HW pg. 749 #4­26 evens 5

6. 11.4 Arc Lengths March 20, 2013
11.4 HW pg. 749 #4­26 evens
Mar 7­10:40 AM
HW pg. 749 #4­26 evens 6