Geometry
Notes – Lesson 7.2
Name __________________________________
Similar: Same _________________ : Different _______________
Similar Polygons: Polygons having corresponding angles_____________________
and corresponding sides _________________________.
Symbol __________.
To find the SIMILARITY RATIO take one side and divide it by its corresponding side.
Are the polygons similar? If they are, write a similarity statement, and find the similarity ratio.
The polygons are similar. Find the values of the variables.
Examples:
1. A painting is 24 in. wide by 36 in. long. The length of a postcard reduction of the painting is 6 in. How wide 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?
Golden Ratio: A Rectangle that can be divided into a _______________
and a _________________ that is similar to the original rectangle.
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 wide.
How high should the canvas be?
A golden rectangle has shorter sides of length 20 cm. Find the length of the longer sides.