1. which reason completes the proof below?
given: bc is tangent to circle a at d
prove: ab = ac

1. C

2. D

3. B

4. C

5. A, B, D

6. B

7. A

8. B, D

9. A, C, D

10. D

Just took it and got 100% ;)

(C)

Step-by-step explanation:

Given: BC is tangent to the circle A at D.

To prove: AB is congruent to AC

Proof:

Statements                                                            Reason

1. BC is tangent to the circle A at D.                     Given

2. DB≅DC                                                               Given

3.AD⊥BC               If a line is tangent to a circle then it is perpendicular to the radius at the point of tangency.

4. ∠ADB and ∠ADC are right angles     Definition of perpendicular lines

5. ∠ADB≅∠ADC                                      Right angles are congruent

6. AD≅AD                                                Reflexive property of congruence

7. ΔADB≅ΔADC                                      SAS rule

8. AB≅AC                                                CPCTC

Hence, option (C) is correct.