Session 66 WarmUp

1
Session 66 Warm-Up

• Solve the proportion .
• Find the value of x.
• Find the value of y.

x 6
x 5
7
5
y
y 9
7
x
18
2
11.3 Perimeter and Area of Similar Figures
3
What needs to be true if two figures are similar?
Sides are proportional
Angles are congruent
In 8.3, you learned that the ratio of
corresponding sides is equal to the ratio of the
perimeters.
8
A
4
10
B
x
4
Find the Area!!
A
For similar figures, ratio of perimeters is
ab. Ratio of areas
is a2b2.
8
Shaded to unshaded
8 4
A
4
10
Reduce 2 1
B
5
22 12
4 1
5
Given the ratio of the area, find the ratio of
the perimeter.
1. 9 121 2. 8 256
3 11
6
Practice Time
WS 11.3
7
11.4 Circumference and Arc Length
8
Circumference
Distance around the circle
9
Circumference
2 p r C
or
dp C
10
Find the circumference.
33 m
14.3 in.
103.7 m
11
Arc Length
Portion of the circumference
A
P
B
12
Find the circumference
Find the arc length
5cm
3.82 m
60º
50º
22.92 m
4.36 cm
13
Practice! 11.4 A
14

Homework Pg. 679 4, 5, 7-16, 20 Pg. 686 6-32
even