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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3. −− BX −− XC 3. Definition of a median. 4. −−− AX −−− AX 4. Reflexive property of congruence. 5. ABX ACX 5. SSS SSS. 6. ABX ACX 6. Corresponding parts of congruent triangles are congruent. 7. Construct a second median, −− BY , from vertex B. 7. A median of a triangle is a line segment with one endpoint at any vertex of the triangle, extending to the midpoint of the opposite side. 8. −− BA −− BC 8. Definition of an equilateral triangle. 9. −− AY −− YC 9. Definition of a median. 10. −− BY −− BY 10. Reflexive property of congruence. 11. BAY BCY 11. SSS SSS. 12. BAY BCY 12. Corresponding angles of congruent triangles are congruent. 13. ABC is equiangular. 13. BCY is the same as ACX, and all three angles of the triangle are equal. 5 mA mC 3x 5 mA mB mC 180 (3x 5) (4x 10) (3x 5) 180 10 x 180 x 18 mC 3(18) 5 59 6 The measure of each angle is 60. So, 3x 6 60; x 22. And 3y 6 60; y 18. 7 Show that RXZ TYZ SYX by SAS SAS, and −− XY −− YZ −− ZX because corresponding parts of congruent triangles are congruent. 8 Construct −− AC and −− BD , and label their intersection E. ABE CBE. −− AC and −− BD are perpendicular. AED and CDE are right angles; therefore, AED CDE. −− AE −− CE . −− ED −− ED . AED CED. CAD ACD. 9 mA mB mC 180 (6x 12) (8x 8) (3x 6) 180 17x 1 0 180 x 10 mA 72; mB 72; mC 36 The triangle is isosceles. 10 mB 180 2x 5-4 Working With Two Pairs of Congruent Triangles (pages 75–76) Note: Since there are many variations of proofs, the following is simply one set of acceptable statements to complete each proof. Depending on the textbook used, the wording and format of reasons may differ, so they have not been supplied for the method of congruence applied in each problem. (These solutions are intended to be used as a guide—other possible solutions may vary.) 1 1. ABC EFG 2. −− AC −− EG 3. −− BD is a median. 4. D is the midpoint (Definition of of −− AC . median) 5. DC 1 _ AC (Definition of mid- 2 point) 6. −− FH is a median. 7. H is the midpoint of −− EG . 8. HG 1 _ EG 2 9. AC EG 10. HG 1 _ AC 2 11. HG DC 5-4 Working With Two Pairs of Congruent Triangles 21

12. −−− HG −−− DC 13. −− FG −− BC 14. BCD FGH 15. BCD FGH (SAS SAS) 16. −− BD −− FH 2 a 1. −− PR and −− QS bisect each other at V. 2. −− PV −− RV 3. −−− QV −− SV 4. PVQ RVS (Vertical angles are congruent.) 5. PQV RSV (SAS SAS) b A continuation of part a. 6. UPV TRV (Corresponding parts of congruent triangles are congruent.) 7. PVU RVT (Vertical angles are congruent.) 8. PUV RTV 3 a 1. (ASA ASA) −− AC −−− AD 2. −− BC −− BD 3. −− AB −− AB 4. ABC ABD (SSS SSS) 5. BAC BAD (Corresponding parts of congruent triangles are 6. congruent.) −− AE −− AE 7. ACD ADE (SAS SAS) b A continuation of part a. 8. 1 2 (Corresponding parts of congruent triangles are 4 1. congruent.) −−− CD −− CB 2. 1 2 3. −− CF −− CF 4. CFB CFD (SAS SAS) 5. CBF CDF 6. EDF ABF 7. BFA EFD 8. (Corresponding parts of congruent triangles are congruent.) −− DF −− BF 9. BFA DFE (ASA ASA) 10. 3 4 (Corresponding parts of congruent triangles are congruent.) 22 Chapter 5: Congruence Based on Triangles 5 1. −− AC −− BC 2. −− AE −− BE 3. −− EC −− EC 4. ACE BCE (SSS SSS) 5. ACE BCE 6. −−− CD −−− CD 7. ACD BCD (SAS SAS) 8. −−− AD −− BD (Corresponding parts of congruent triangles are congruent.) 6 a 1. −− SP −−− QR 2. 1 2 3. −− AB bisects −− QS at C. 4. −− SC −−− QC (Definition of bisector) 5. −− SQ −− SQ 6. SQP QSR (SAS SAS) 7. SQP QSR (Corresponding parts of congruent triangles are congruent.) 8. ACQ BCS 9. ACQ BCS (ASA ASA) b Continuation of part a. 10. −− AC −− BC (Corresponding parts of congruent triangles are congruent.) 5-5 Proving Overlapping Triangles Congruent (page 77) Note: Since there are many variations of proofs, the following is simply one set of acceptable statements to complete each proof. Depending on the textbook used, the wording and format of reasons may differ, so they have not been supplied for the method of congruence applied in each problem. (These solutions are intended to be used as a guide—other possible solutions may vary.) 1 1. −− AE −− BE 2. EAB EBA (If two sides of a triangle are congruent, the angles opposite these sides are congruent.)

12. −−−<br />

HG −−−<br />

DC<br />

13. −−<br />

FG −−<br />

BC<br />

14. BCD FGH<br />

15. BCD FGH (SAS SAS)<br />

16. −−<br />

BD −−<br />

FH<br />

2 a 1. −−<br />

PR and −−<br />

QS bisect each o<strong>the</strong>r at V.<br />

2. −−<br />

PV −−<br />

RV<br />

3. −−−<br />

QV −−<br />

SV<br />

4. PVQ RVS (Vertical angles are<br />

congruent.)<br />

5. PQV RSV (SAS SAS)<br />

b A continuation of part a.<br />

6. UPV TRV (Corresponding<br />

parts of congruent<br />

triangles are<br />

congruent.)<br />

7. PVU RVT (Vertical angles are<br />

congruent.)<br />

8. PUV RTV<br />

3 a 1.<br />

(ASA ASA)<br />

−−<br />

AC −−−<br />

AD<br />

2. −−<br />

BC −−<br />

BD<br />

3. −−<br />

AB −−<br />

AB<br />

4. ABC ABD (SSS SSS)<br />

5. BAC BAD (Corresponding<br />

parts of congruent<br />

triangles are<br />

6.<br />

congruent.)<br />

−−<br />

AE −−<br />

AE<br />

7. ACD ADE (SAS SAS)<br />

b A continuation of part a.<br />

8. 1 2 (Corresponding<br />

parts of congruent<br />

triangles are<br />

4 1.<br />

congruent.)<br />

−−−<br />

CD −−<br />

CB<br />

2. 1 2<br />

3. −−<br />

CF −−<br />

CF<br />

4. CFB CFD (SAS SAS)<br />

5. CBF CDF<br />

6. EDF ABF<br />

7. BFA EFD<br />

8.<br />

(Corresponding<br />

parts of congruent<br />

triangles are<br />

congruent.)<br />

−−<br />

DF −−<br />

BF<br />

9. BFA DFE (ASA ASA)<br />

10. 3 4 (Corresponding<br />

parts of congruent<br />

triangles are<br />

congruent.)<br />

22 Chapter 5: Congruence Based on Triangles<br />

5 1. −−<br />

AC −−<br />

BC<br />

2. −−<br />

AE −−<br />

BE<br />

3. −−<br />

EC −−<br />

EC<br />

4. ACE BCE (SSS SSS)<br />

5. ACE BCE<br />

6. −−−<br />

CD −−−<br />

CD<br />

7. ACD BCD (SAS SAS)<br />

8. −−−<br />

AD −−<br />

BD<br />

(Corresponding<br />

parts of congruent<br />

triangles are<br />

congruent.)<br />

6 a 1. −−<br />

SP −−−<br />

QR<br />

2. 1 2<br />

3. −−<br />

AB bisects −−<br />

QS at C.<br />

4. −−<br />

SC −−−<br />

QC (Definition of<br />

bisector)<br />

5. −−<br />

SQ −−<br />

SQ<br />

6. SQP QSR (SAS SAS)<br />

7. SQP QSR (Corresponding<br />

parts of congruent<br />

triangles are<br />

congruent.)<br />

8. ACQ BCS<br />

9. ACQ BCS (ASA ASA)<br />

b Continuation of part a.<br />

10. −−<br />

AC −−<br />

BC (Corresponding<br />

parts of congruent<br />

triangles are<br />

congruent.)<br />

5-5 Proving Overlapping<br />

Triangles Congruent<br />

(page 77)<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 />

1 1. −−<br />

AE −−<br />

BE<br />

2. EAB EBA (If two sides of<br />

a triangle are congruent,<br />

<strong>the</strong> angles<br />

opposite <strong>the</strong>se sides<br />

are congruent.)

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