Preparing for the Regents Examination Geometry, AK
Preparing for the Regents Examination Geometry, AK
Preparing for the Regents Examination Geometry, AK
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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