Download 9.3 Class Notes

Section 9.3
Arcs and Central Angles
Name
Period #
Definition 1: A ____________________ angle is an angle with its vertex at the center of the circle.
Definition 2: An _____________ is an unbroken part of a circle.
Definition 3: If Y and Z are the endpoints of a diameter, then the two arcs are called __________________.
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Use 3 letters to name a semicircle or major arc. _______________ arcs can be named with 2.
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The measure of a minor arc is defined to be the measure of its _____________________ angle.
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The measure of a major arc is __________ minus the measure of its _____________ arc.
Definition 4: ________________________ arcs of a circle are arcs that have exactly one point in common.
The following postulate can be used to find the measure of an arc formed by 2 adjacent arcs:
Definition 5: ________________________ arcs are arcs, in the same circle or in congruent circles that have
equal measures.
Ex 1: Name the congruent arcs in the figures below: