12.2 Arcs and Chords Key Vocabulary

Word Definition Picture

Central Angle

Arc

Minor Arc

Major Arc

Semicircle

More about Arcs!!

Word Definition Picture

Adjacent Arcs

Arc addition

Postulate

Congruent Arcs

Practice

1) mHJ 2) mCDE

mFGH mBCD

Angle and Chord Theorems

Theorem Hypothesis Conclusion

Congruent central angles have congruent chords.

mBEA mCED

.BA CD

Congruent chords have congruent arcs.

BA CD

.BA CD

Congruent arcs have congruent central angles.

BA CD

mBEA mCED

Practice: Find the value of the variable and the missing measures.

1) 2)

3) 4)

More Theorems!!!

Theorem Hypothesis Conclusion In a circle, if a radius or diameter is perpendicular to a chord, then it bisects the chord and its arc.

In a circle, the perpendicular bisector of a chord is a radius. (or diameter)

Practice:

1) Find NP 2)Find LN

More Practice!

1) Find mNGH and HL 2) Find mUTW