Circle
Angles associated with a circle:
Central Angle - an angle whose vertex is at the center of the circle
Inscribed Angle - an angle whose vertex is ON the circumference of the the circle
Interior Angle- an angle whose vertex is IN the circle, but not at the center.
Exterior Angle - an angle whose vertex is outside the circle
A central angle is made from 2 radii and its measure is EQUAL to the intercepted arc (The arc it cut)
An inscribed angle is made from 2 chords (or a chord and a tangent) and its measure is equal to HALF of the intercepted arc.
An interior angle is made from 2 chords or secants and its measure is equal to 1/2(major arc + minor arc)
An Exterior angle is made of 2 tangents or 2 secants and its measure is equal to 1/2(major arc - minor arc)
THEOREMS ABOUT CHORDS, SECANTS AND TANGENTS:
equal arcs have equal chords
equal chords have equal arcs
two tangents from the same point are congruent
the tangent is perpendicular to the radius it touches
if a radius is perpendicular to a chord then it bisects the chord
Answers: 1) 60 2) 85 3) 2 4) 60 5) 75 6) 250 7) 140 8) true 9) true 10)15
Geometry Practice with circles.PDF
Practice finding lengths of chords segments, secants and tangents.
