1. Use Similar Polygons & AA Postulate
6.3 & 6.4
Use Similar Polygons & AA Postulate

2. SIMILAR POLYGONS Similar Polygons-Same Shape
Corresponding angles are congruent
Corresponding side lengths are proportional

3. List all pairs of congruent angles
List all pairs of congruent angles. Write the ratios of the corresponding sides.

4. EXAMPLE
List all pairs of congruent angles. Write the ratios of corresponding sides in a statement of proportionality.

5. Scale Factor
If two polygons are similar, then the ratio of the lengths of two corresponding sides is called the scale factor.

6. Determining Similarity
Determine whether the polygons are similar. If they are similar, find the scale factor.

7. Determine whether the polygons are similar
Determine whether the polygons are similar. If they are similar, find the scale factor.

8. Determine whether the polygons are similar
Determine whether the polygons are similar. If they are similar, find the scale factor.

9. Perimeters of Similar Polygons
Perimeter: Sum of the sides of a polygon
Ratio of the perimeters = Ratio of corresponding sides
Ratio of corresponding lengths=scale factor
Altitudes, Medians, Angle Bisectors…

10. Find the scale factor of the polygon on the left to the one on the right. Find the perimeter of each polygon.

11. Find the scale factor of the polygon on the left to the one on the right. Find the perimeter of each polygon.

12. Are the two triangles similar?
What do we need to know?
Corresponding angles are congruent
All corresponding sides have the same proportion
Would a simpler way be nice?

13. Angle-Angle Triangle Similarity
If two angles of one triangle are congruent to two angles of another triangle, then the two triangles are similar.
This can only be used for triangles!

14. Determine whether the triangles are similar
Determine whether the triangles are similar. If yes, write the similarity statement.

15. Determine whether the triangles are similar
Determine whether the triangles are similar. If yes, write the similarity statement. 1. 2.

16. Indirect Measurement
When given similar triangles, write a proportion to find missing side lengths.