Geometry A Unit 4 Day 5 HW Help
In General, proofs in Unit 4 go like this…
1. Use given statements and known theorems to determine three sets of congruent corresponding parts in
the two triangles.
2. Use SSS, SAS, ASA, AAS or HL as the reason for saying two triangles are congruent.
3. If you are asked to prove that other corresponding parts are congruent, then once you’ve completed the
two steps above, you can use the reason CPCTC to do so.
p. 233 #14 Hint: Use the general plan above and the clues given to you in the text book.
p. 233 #15 Hint: The proof is done in 2 parts. We want to prove that  AFB   EFD, but getting
three sets of congruent corresponding parts is impossible unless we first show  AFC   EFC (Steps
1-4). Once we have that, we can take advantage of the fact that one pair of corresponding parts in
triangles  AFC   EFC (AF and EF) are also corresponding parts of the triangles we ultimately are
trying to prove are congruent.
17.
Statement
1. ___________________
Reason
1. __________________
2. ___________________ 2. ___________________
3.  T = 90o ; R = 90o
3. ___________________
4. __________________
4. Transitive
5. ___________________
5.
6. ___________________
6. _____________________
Alternate Interior Angles
7. ____________________ 7. ____________________
8. _____________________ 8. _____________________
See next page for help on #18
18.
1. _________________________ 1. __________________________
2. _________________________ 2. __________________________
3.  BDC =  ADB = 90o
3.
Lines form 4 = 90o angles
4. _________________________ 4. __________________________
5. _________________________
5. _________________________
6. _________________________ 6.
7. ___BAD
= ___BCD


SAS
7. ______________________
8.  ABD + BDA +  BAD = 180o 8. ______________________
9. ___________________________ 9. _____Substitution__________
10. ____________________________ 10. _________________________
11. ____________________________ 11. Definition of complementary