1 / 14

Section 8.3 Proving Triangles Similar

Section 8.3 Proving Triangles Similar. By: Asad Ashraf. What is Similarity. Similar figures are figures in which the shape is exactly the same, but the size is not. A Dilation is an enlargement of a figure. It is still similar, however.

enya
Download Presentation

Section 8.3 Proving Triangles Similar

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Section 8.3Proving Triangles Similar By: Asad Ashraf

  2. What is Similarity • Similar figures are figures in which the shape is exactly the same, but the size is not. • A Dilation is an enlargement of a figure. It is still similar, however. • A Reduction is a reduction of a figure. This is also similar. • **Remember that similar figures are not necessarily congruent**

  3. Proving Triangles Similar • There are several methods to prove triangles similar. • These are very similar to the methods of proving triangles congruent. • The methods are AAA~, AA~, SAS~, and SSS~.

  4. AAA~ Postulate • AAA~  Postulate  - If three angles of one triangle are congruent to three angles of a 2nd triangle then the triangles are similar.

  5. AA~ Theorem • AA~ if 2 angles of one triangle are congruent to two angles of a 2nd triangle then the triangles are similar. • This is proved by the No-Choice Theorem and AAA~ Theorem combined.

  6. SSS~ Theorem • SSS~ If 3 sides of one triangle are proportional to three sides of a 2nd triangle then the two triangles are similar.

  7. SAS~ Theorem • SAS ~  If two sides of one triangle are proportional to the corresponding two sides of a 2nd triangle and their included angles are congruent, then the triangles are similar.

  8. Sample Problems • Click Here • SSS~ and SAS~ Problems

  9. Sample Problems Are these triangles ~? Answer: Yes they are because Included angles were given congruent and the ratios of the sides are congruent as well.

  10. Practice Problems • Prove that an acute angle of one right angle is congruent to the vertex angle of an isosceles triangle, they are similar. • Always, Sometimes, Never • If 2 triangles are similar, they are congruent ____ • If 2 triangles are congruent, they are similar ____ • 2 rectangles are similar if neither is a square ____ • 2 right triangles are similar____ Answers: A, S, S, S

  11. Practice Problems • Are any 2 isosceles triangles similar? Show all work.

  12. Practice Problems • Are these triangles similar? Why or why not? Answer: NO

  13. Practice Problems • Given: XS and RY are Altitudes of RTS • Prove: Triangle TSX is similar to Triangle TYR

  14. Works Cited • Our Book • “Similar Triangles”. Mathwarehouse.com. May 27,2008.<http://www.mathwarehouse.com/geometry/similar/triangles/index.html>. • “Chapter 8”. Teacherweb.org. 2003. May 27,2008.<http://teacherweb.ftl.pinecrest.edu/wingjoa/My%20Webs/Geometry/chpt8.htm#Test%20Review%20-%20%20Chapter%208.1-4>.

More Related