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Aim: How to prove triangles are congruent using a 4 th shortcut: AAS. Do Now:. What method shows these triangles to be congruent?. ASA. SAS. Angle-Angle-Side. IV. AAS = AAS. A. A’. B. C. B’. C’. If A = A', C = C', BC = B’C', then D ABC = D A'B'C'.
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Aim: How to prove triangles are congruent using a 4th shortcut: AAS. Do Now: • What method shows these triangles to be congruent? ASA SAS
Angle-Angle-Side IV.AAS = AAS A A’ B C B’ C’ If A = A', C = C', BC = B’C', then DABC = DA'B'C'. IfAAS AAS, then the triangles are congruent Two triangles cannot be proved to be congruent by AAA AAA or SSA SSA
Model Problems Is the given information sufficient to prove congruent triangles? C D NO YES A B YES YES
Model Problem BD bisects B and A C. Explain why ADB CDB. ABD CBD – angle bisector cuts angle into two congruent parts (A A) A C – I’m told so - Given (A A) BD BD – anything is equal to itself - Reflexive Property (S S) ADB CDB because ofAAS AAS
RM PM RM PM – Corresponding parts of congruent triangles are congruent CPCTC Model Problem - CPCTC RMP bisects AMB at M, and R P. Explain why RM PM AM MB – bisector cuts segment into two congruent parts (S S) R P – I’m told so - Given (A A) RMA PMB – Vertical angles are (A A) RMA PMB because ofAAS AAS