geometry chords and arcs, assignment help

he circles below are congruent. Which conclusion can you draw using the circles.

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Complete the proof of theorem 12-6

Which reason can be used for blank b?

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a. Within a circle or in congruent circles, congruent chords have congruent central angles.

b. Within a circle or in congruent circles, congruent chords have congruent arcs.

c. Vertical arcs are congruent.

d. Within a circle or in congruent circles, congruent central angles have congruent arcs.

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a, 90°

b. 108°

c. 72°

d. 162°

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a. 45°

b. 60°

c. 90°

d. 180°