24.09.2013 Views

Preparing for the Regents Examination Geometry, AK

Preparing for the Regents Examination Geometry, AK

Preparing for the Regents Examination Geometry, AK

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

14 a 3 : 2 b QR 10, RS 20,<br />

ST 12, PT 22<br />

15 a True b False c True<br />

d True e False f True<br />

g False h False<br />

16 If <strong>the</strong> vertex angles are congruent, <strong>the</strong>n <strong>the</strong><br />

base angles must also be congruent. Similarly,<br />

if <strong>the</strong> base angles are congruent, <strong>the</strong>n<br />

<strong>the</strong> vertex angles are congruent. Triangles are<br />

similar by (AA) or (AAA).<br />

12-4 Proving Triangles<br />

Similar<br />

(pages 307–308)<br />

1 (2) similar<br />

2 Vertical angles are congruent. (AA)<br />

3 Not similar<br />

Note: Since <strong>the</strong>re are many variations of proofs,<br />

<strong>the</strong> following is simply one set of acceptable<br />

statements to complete each proof. Depending<br />

on <strong>the</strong> textbook used, <strong>the</strong> wording and <strong>for</strong>mat<br />

of reasons may differ, so <strong>the</strong>y have not been<br />

supplied <strong>for</strong> <strong>the</strong> method of congruence applied<br />

in each problem. (These solutions are intended<br />

to be used as a guide—o<strong>the</strong>r possible solutions<br />

may vary.)<br />

4 a 1. −−<br />

AE −−<br />

BC<br />

2. BCD DAE ( Alternate interior<br />

angles)<br />

3. −−<br />

AC and −−<br />

BE intersect at D.<br />

4. BDC ADE (Vertical angles)<br />

5. ADE CDB (AA)<br />

b AD 30<br />

5 All corresponding sides are in<br />

proportion; AB _ <br />

BE<br />

CD _ <br />

AE<br />

CE _ <br />

4<br />

DE _ . Triangles<br />

5<br />

are similar.<br />

6 4 _ and<br />

6 5 _ , corresponding sides are not in<br />

3<br />

proportion. Triangles are not similar.<br />

7 6 _ and<br />

7 4 _ , corresponding sides are not in<br />

5<br />

proportion. Triangles are not similar.<br />

8 1. −−−<br />

CD −−<br />

AB<br />

2. CDA and CDB are right angles.<br />

3. CDA CDB<br />

4. CAD CBD<br />

5. CAD CBD (AA)<br />

74 Chapter 12: Ratios, Proportion, and Similiarity<br />

9 1. −−<br />

AB −−<br />

DE<br />

2. EDF BAC (Corresponding<br />

angles are<br />

congruent.)<br />

3. −−<br />

BC −−<br />

EF<br />

4. EFD BCA<br />

5. ABC DEF (AA)<br />

10 1. −−<br />

BE −−<br />

AC and −−−<br />

CD −−<br />

AB<br />

2. HEC and HDB are right angles.<br />

3. HEC HDB<br />

4. DHB CHE (Vertical angles are<br />

congruent.)<br />

5. EHC DHB (AA)<br />

11 1. −−<br />

DE −−<br />

BC and −−<br />

DF −−<br />

AB<br />

2. DEC and DFA are right angles.<br />

3. DEC DFA<br />

4. Parallelogram ABCD<br />

5. FAD ECD<br />

6. AFD CED (AA)<br />

12 1. DBE ADF<br />

2. BAC BDE (Corresponding<br />

angles)<br />

3. B B<br />

4. DBE ABC (AA)<br />

13 1. Parallelogram ABCE<br />

2. −−−<br />

AED<br />

3. −−<br />

BC −−<br />

AE<br />

4. −−<br />

BC −−−<br />

AD<br />

5. CBF ADB (Alternate interior<br />

angles)<br />

6. BAD FCB<br />

7. BAD FCB (AA)<br />

14 1. ABC PQR<br />

2. ABC PQR<br />

3. −−<br />

BD bisects ABC.<br />

4. −−<br />

QS bisects PQR.<br />

5. ABD PQS<br />

6. BAD QPS<br />

7. ABD PQS (AA)<br />

15 1. Parallelogram ABCD<br />

2. −−−<br />

AD −−<br />

BC<br />

3. GAE BCG (Alternate interior<br />

angles are<br />

congruent.)<br />

4. −−<br />

AC bisects HAE.<br />

5. HAG GAE<br />

6. HAG BCG<br />

7. −−−<br />

AH −−<br />

AE

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!