1. Unit 4: Similarity
Honors Geometry

2. Review Test

3. 8.1 Ratios and Proportions
Objectives
To write ratios and solve proportions
To identify similar polygons
To apply similar polygons

4. 8.1 Ratios and Proportions
A ratio is a comparison of two quantities.
a to b
a : b
, b ≠ 0.
A proportion is a statement that two ratios are equal. or

5. Properties of Proportions
If then ad=bc (Cross Product Property)

6. AND:
If , then…

7. Example – Solve 1.

8. Example – Solve 2.

9. Example – Solve 3.

10. 8.2 Similar Polygons
Similar Polygons - Two figures that have the same shape but not necessarily the same size
Symbol: ~

11. Similar Polygons Two polygons are similar if and only if:
Corresponding angles are congruent
AND
Corresponding sides are proportional
Example:

12. Similarity Ratio (Scale Factor)
The ratio of the lengths of corresponding sides is the similarity ratio 15
Similarity Ratio= 5

13. Example ∆ABC ~ ∆JKL Find the similarity Ratio of Find the value of x.
Find m<J

14. Donald Duck in Mathmagic Land
As we watch the video, be sure to fill out your worksheet
Donald Duck in Mathmagic Land

15. Homework
Worksheet