Circle Review

Circle Review

Vocabulary of a Circle

• Radius

• Diameter

• Chord

• Tangent

• Secant

• Arc

Arcs of a Circle

• Minor Arc

• Major Arc

• Semicircle

Adjacent Arcs vs. Non-Adjacent Arcs

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Arc Addition Postulate

Circles

• Tangent Circles

• Concentric Circles

• Congruent Circles

Tangents of a Circle

• If a line is tangent to a circle, then the line is perpendicular to the radius at the point of tangency

• If two tangent segments to a circle share a common endpoint outside the circle, then the two segments are congruen

Chords of a Circle

• In a circle, if a radius (or diameter) is perpendicular to a chord, then it bisects the chord and its arc.

Inscribed Angles

• The measure of an inscribed angle is half the measure of its intercepted arc.

• If inscribed angles of a circle interecept the same arc, then the angles are congruent.

• An inscribed angle is a right angle if its intercepted arc is a semicircle.

• If a quadrilateral is inscribed in a circle, then its opposite angles are supplementary.

Angle Relationships in Circles

• Vertex on the circle

• Vertex in the interior of the circle

• Vertex in the exterior of the circle.

Equation of a Circle (Standard Form)

• (x - h)² + (y - k)² = r²

Arc Length

Area of a Sector