Which of the following equations is equivalent to y=4x-8 ? a.y=x-2b. y=2x-4 c. 3y=12x-24 d. y / 2 =2x warm-up 2

Happy Thanksgiving 4.1 Congruent Figures You will justify and apply polygon congruence relationships You will name and label corresponding parts of congruent polygons

First, we need to look at some things.  What makes two items congruent?  All the corresponding sides are congruent.  All the corresponding angles are congruent. Pardekooper

Labeling an angle or a side in correct order is very important. Lets see if you can do it.

 LMC  BJK. Complete the following statements. 1.LC  _____ 2.KJ  _____ 3.JB  _____ 4.  L  _____ 5.  K  _____ 6.  M  _____ 7.  CML  _____ 8.  KBJ  _____ 9.  MLC  _____ 10.  JKB  _____ BK CM ML B C J KJB CLM JBK MCL Pardekooper

Lets label the congruent parts L NM P Q R  N  R  L  P  M  Q NL  RP LM  PQ NM  RQ  NLM   RPQ

AT S BC FNow it’s you turn to label all the congruent parts for the triangles.  A  C  S  F  T  B AS  CF ST  FB TA  BC  AST   CFB

There is a theorem. If two angles of one triangle are congruent to two angles of another triangle, then the third angle is congruent

Next comes a proof. {Remember to label all of the given.} Given: PQ  PS, QR  SR,  Q  S,  QPR  SPR Prove:  PQR  PSR P Q R S StatementReason Remember all parts must be congruent. 1. Given 1. PQ  PS, QR  SR 2. Reflexive 2. PR  PR X 3. Given 3.  Q  S,  QPR  SPR 4. If 2  ’s are , then 3rd  is  4.  QRP  SRP 5. All parts , figures are  5.  QRP  SRP Pardekooper

What do you need to prove the following triangles congruent? 3rd pair of  ‘s  3rd pair of sides 