1. Proving Triangles Congruent – SSS, SAS
LESSON 4–4
Proving Triangles Congruent – SSS, SAS

2. Write a congruence statement for the triangles.
A. ΔLMN  ΔRTS
B. ΔLMN  ΔSTR
C. ΔLMN  ΔRST
D. ΔLMN  ΔTRS
5-Minute Check 1

3. Name the corresponding congruent angles for the congruent triangles.
A. L  R, N  T, M  S
B. L  R, M  S, N  T
C. L  T, M  R, N  S
D. L  R, N  S, M  T
5-Minute Check 2

4. Name the corresponding congruent sides for the congruent triangles.
A. LM  RT, LN  RS, NM  ST
B. LM  RT, LN  LR, LM  LS
C. LM  ST, LN  RT, NM  RS
D. LM  LN, RT  RS, MN  ST
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5-Minute Check 3

5. Refer to the figure. Find x.
A. 1
B. 2
C. 3
D. 4
5-Minute Check 4

6. Refer to the figure. Find m A.
B. 39
C. 59
D. 63
5-Minute Check 5

7. Given that ΔABC  ΔDEF, which of the following statements is true?
A. A  E
B. C  D
C. AB  DE
D. BC  FD
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5-Minute Check 6

8. You proved triangles congruent using the definition of congruence.
Use the SSS Postulate to test for triangle congruence.
Use the SAS Postulate to test for triangle congruence.
Then/Now

9. included angle
Vocabulary

10. Concept 1

11. Write a flow proof. ___ Given: QU  AD, QD  AU Prove: ΔQUD  ΔADU
Use SSS to Prove Triangles Congruent
Write a flow proof.
Given: QU  AD, QD  AU
___
Prove: ΔQUD  ΔADU
Example 1

12. Which information is missing from the flowproof. Given:. AC  AB
Which information is missing from the flowproof? Given: AC  AB D is the midpoint of BC. Prove: ΔADC  ΔADB
___
A. AC  AC
B. AB  AB
C. AD  AD
D. CB  BC
___
Example 1 CYP

13. Concept 2

14. Use SAS to Prove Triangles are Congruent
ENTOMOLOGY The wings of one type of moth form two triangles. Write a two-column proof to prove that ΔFEG  ΔHIG if EI  FH, and G is the midpoint of both EI and FH.
Example 3

15. A. Reflexive B. Symmetric C. Transitive D. Substitution
The two-column proof is shown to prove that ΔABG  ΔCGB if ABG  CGB and AB  CG. Choose the best reason to fill in the blank. 1.
Reasons
Proof:
Statements
1. Given
2. ? Property 2.
3. SSS
3. ΔABG ΔCGB
A. Reflexive B. Symmetric
C. Transitive D. Substitution
Example 3

16. Write a paragraph proof.
Use SAS or SSS in Proofs
Write a paragraph proof.
Prove: Q  S
Example 4

17. Proving Triangles Congruent – SSS, SAS
LESSON 4–4
Proving Triangles Congruent – SSS, SAS