Dorchester - 01-09-2025 Triangle Congruence - SSS, SAS, ASA ;

Thursday, January 9, 2025

Open Ended

Which one doesn't belong

Congruent Triangle Theorems

SSS, SAS, ASA, AAS, HL

4) 01-09-2025 -NOTES- SSS SAS, ASA with Congruent Triangles

Follow along to make sure notes are complete and correct-This will be quick!

Open NOTES

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​Corresponding Parts

​In a previous lesson, you learned that if all six pairs of corresponding parts (sides and angles) are congruent, then the triangles are congruent

Match

Match the congruent parts

• Angle A

• $$\overline{EF}$$

• $$\overline{FE}$$

• $$\angle B$$

• $$\angle F$$

Angle D

• Angle D

• $$\overline{BC}$$

• $$\overline{CB}$$

• $$\angle E$$

• $$\angle C$$

Multiple Choice

If ∆LMK ≅ ∆LMT, then ∠K ≅ ____

• MT

• ∠T

• ∠M

• ∠L

​Do you need to show that all six parts are congruent???​

​Triangle Congruence Shortcuts

​​Side-Angle-Side (SAS)

What is an ​Included Angle?​

Name the Included Angle...

​***For this activity, complete problem #2 on your paper!

​Name the Included Angle...

​Name the Included Angle...

​Angle-Side-Angle (ASA)​

​Angle-Side-Angle (ASA)​

​If two angles and the included side of one triangle are congruent to the two angles and the Included side of another triangle, then the triangles are congruent.​

​What is an Included Side?

​The side between two angles

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​​This combo is called angle-side-angle, or just ASA.​

​Name the Included Side...

​***For this activity, complete problem #3 on your paper!

​Name the Included Side...

​Name the Included Side...

​Name the Included Side...

​Warning: No SSA Postulate​

​Warning: No SSA Postulate​

​BUT: SSA DOES work in one​ situation!​

​WE CALL THIS...

​Hypotenuse-Leg (HL)​

​If the hypotenuse and a leg of a right triangle are congruent to the hypotenuse and a leg of another right triangle, then the triangles are congruent.

​​Hypotenuse-Leg (HL)

​Side-Side-Side (SSS)​

​If the sides of one triangle are congruent to the sides of a second triangle, then the triangles are congruent.​

​Side-Side-Side (SSS)​

​If the sides of one triangle are congruent to the sides of a second triangle, then the triangles are congruent.​

Poll

What is your confidence level on using CPCTC, SSS, SAS, and ASA with congruent triangles?

• Super Confident

• Confident

• I may have a few questions

• I'm lost!