agenda 1.investigation 2.8-3 proving triangles are similar 3.class work 4.homework
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Agenda1. Investigation
2. 8-3 Proving Triangles are Similar
3. Class Work
4. Homework
Warm Up1 State if the following figures are similar
2 The two triangles are similar. Solve for x.
Homework Check3. 3b 4. 4/3 5. b/4 6. b/a 7. 3/a 8. 4a
9. 7/4 10. 3/7 11. (b+4)/4 12. 4 13. 5/3
14. 4 15. 6.875 16. 7.2 17. 7.2 18. 7.5
19. 14 20. 7 26. 13:6 27. 5:4 28. 4:3
Homework Check contd
1.JHY 2. R 3. JXY 4. HY 5. JT 6. HY
9. yes, KLMJ~PQNO; 3/5 10. yes; ABCD~FGHE;4/5
11. No; corr angles are not congruent
12. yes; ABC~FED; 7/5
13. x=4, y=3 14. x=20, y=17.5, z=7.5
15. x=16, y=4.5, z=7.5 16. x=6, y=8, z=10
Investigation: Triangles with Two Pairs of Congruent AnglesWith a partner, complete the Investigation
Worksheet.
Answer both questions
8-3 Proving Triangles are Similar
3 ways to prove Triangles are Similar:
1. AA ~If two angles of one triangle are congruent to two angles of
another triangle, then the triangles are similar
Similarity Statement:
2. SAS ~
If 2 sides of a triangle are proportional to two sides of another triangle AND the included (in between) angles are congruent, then the triangles are similar.
Similarity Statement:
3. SSS ~
If all 3 corresponding sides of two triangles are proportional, then the triangles are similar
Similarity Statement:
Indirect Measurement using similar triangles often uses one of these two facts:
1. Light reflects off a mirror at the same angles at which it hits the mirror.
Similar By:
2. Similar Triangles are formed by figures and their shadows
Similar By:
Examples:
For each of the following, explain why the triangles are similar and write a similarity statement
Class Work8-3 Practice in Book
Problems 1-9
Homework Complete the worksheet
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