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Preparing for the Regents Examination Geometry, AK

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16 Score Explanation<br />

4 The following proof or ano<strong>the</strong>r appropriate proof is given.<br />

Right angles B and A are congruent because −−<br />

AB −−<br />

DB and<br />

−−<br />

AC −−−<br />

DC . −−−<br />

BW −−−<br />

CW . BWA CWD because vertical angles are congruent.<br />

There<strong>for</strong>e, by ASA ABW DCW. −−−<br />

AW −−−<br />

DW because of CPCTC. Hence, AWD is<br />

isosceles by definition of an isosceles triangle.<br />

3 An appropriate proof with correct conclusion is shown, but one reason is faulty and/or<br />

one statement is missing.<br />

2 An appropriate proof with correct conclusion is used, but multiple reasons are faulty or<br />

multiple steps are missing or have errors.<br />

1 AWD is isosceles and a reason is given, but no appropriate method is shown.<br />

0 A zero response is completely incorrect, irrelevant, or incoherent or is a correct response<br />

that was obtained by an obviously incorrect procedure.<br />

17 Score Explanation<br />

4 The following proof or ano<strong>the</strong>r appropriate proof is given.<br />

Statements Reasons<br />

1. BC AB 1. Given.<br />

2. mBAC mBCA 2. The measures of <strong>the</strong> angles opposite unequal<br />

sides are unequal.<br />

3. 1 _ mBAC <br />

2 1 _ mBCA 3. Division postulate.<br />

2<br />

4. −−−<br />

DA bisects BAC. 4. Given.<br />

5. mDAC 1 _ mBAC 5. Definition of a bisector.<br />

2<br />

6. −−−<br />

DC bisects BCA. 6. Given.<br />

7. mDCA 1 _ mBCA 7. Definition of a bisector.<br />

2<br />

8. mDAC mDCA 8. Substitution postulate.<br />

9. DC DA 9. The lengths of <strong>the</strong> sides opposite two unequal<br />

angles of a triangle are unequal.<br />

3 An appropriate proof with correct conclusion is shown, but one reason is faulty and/or<br />

one statement is missing.<br />

2 An appropriate proof with correct conclusion is used, but multiple reasons are faulty or<br />

multiple steps are missing or have errors.<br />

1 DC DA and a reason is given, but no appropriate method is shown.<br />

0 A zero response is completely incorrect, irrelevant, or incoherent or is a correct response<br />

that was obtained by an obviously incorrect procedure.<br />

Chapters 1–7 111

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