Download Lesson 7.2 Notes

Notes – Lesson 7.2
Geometry
Name __________________________________
Definition of Similar: Two figures that have the ___________________________________________ but not necessarily the
_________________________________________ are similar.
The symbol used for similar is __________.
Two polygons are similar if:
 corresponding angles are _______________________ and the corresponding sides are ___________________________
Example.
ABCD is similar to EFGH. Complete each statement.
1.
 E =  _________ which equals _________ degrees.
2.
 B =  _________ which equals __________ degrees.
3.
AB AD

EF
4.
GH FG

CD
Are the polygons similar? If they are, write a similarity statement, and find the similarity ratio.
1.
2.
3.
4.
5.
6.
The polygons are similar. Find the values of the variables.
1.
2.
3.
4.
Real World Problems.
1. A painting is 24 in. wide by 36 in. long. The length of a postcard reduction of the painting is 6 in. How side is the postcard?
2. A map has dimensions 9 in. by 15 in. You want to reduce the map so that it will fit on a 4 in. by 6 in. index card. What are
the dimensions of the largest possible complete map that you can fit on the index card?
3. A company logo is a rhombus with 4-cm sides and angles of 60o and 120o. Find the angle measures and side lengths if the
logo is changed as follows.
a. reduced by 20%
b. reduced to 20%
sides ___________
sides ___________
angles _________ and __________
angles __________ and _____________
Golden Ratio ______ : _______
(length)
(width)
Example
An Artist plans to paint a picture. He wants the canvas to be a golden rectangle with its longer horizontal sides 30 cm side.
How high should the canvas be?
A golden rectangle has shorter sides of length 20 cm. Find the length of the longer sides.