1. Section 8.3 Similar Polygons

2. Similar Figures Two figures that have the same shape are similar
Not necessarily the same size!
Enlarging and shrinking

3. Real life example of Similarity

7. Similar Polygons Two polygons are similar if:
corresponding angles have the same measure
corresponding sides are in proportion
Symbolic notation for similarity: ~

8. Congruent vs. Similar

9. Congruence Similarity Similarities
Figures are the exact same size and shape
Corresponding sides are equal
Corresponding angles are equal
Figures have the same shape but not necessarily the same size.
Corresponding sides are in
proportion
Corresponding angles are equal
Similarities
Both have corresponding angles that are equal.
Same shape of the object
Both have a symbolic notation

10. Example of Similar Polygons
Similarity
Statement
ABCD ~ EFGH
Statement of Proportionality
________ = _________ =__________=_________

11. How to determine similarity:
Are corresponding angles equal?
Are corresponding sides in proportion?
Are the ratios the same?

12. Are they similar?

13. Are they similar?

14. Scale Factor
Ratio of the lengths of two corresponding sides of similar figures.
Corresponding sides change by the same scale factor.
What does this mean?

15. It means that all the sides of the small figure are multiplied by the same number to obtain the lengths of the corresponding sides of the large figure.

16. Find the scale factor.

17. Find the scale factor.