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Circle Vocab and properties of Circles

learning vocab terms, and properties about angles in circles.
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Chord
A line that passes through the circle, but does not pass through the center.
Diameter
a line that passes through the center of the circle.
Radius
a line that touches the center of the circle and the edge of the circle.
Semicircle
half a circle; 180 degress
Central Angle
the vertx of the angle measure is in the center of the circle
Inscribed Angle
the vertex of the measure angle is on the edge of the circle. The vertex will be doubled to find the measure of the arc, or the central angle. Any two vertextes may be placed inside the circle and they will alway share the same arc measure if the endpoints are the same.
Angles Inscribed in a Semicircle
will always be a 90 degress, since the arc is 180 degress.
Intersecting Chords
When two chords cross over each other, you'll be left with four ''legs'' multiply the opposite legs together to find x. set up a porportion.
Congruent Chords
the arcs will be the same. the central angles are congruent.
Secant
a line that intersects the circle at two points
Tangent
touches the circle at one point, will nevr e inside the circle, it will only ever touch the outside of the circle. The point of tangency. a radius touching a tangent will always make a 90 degress angle.
Inscribed Quadrilaterals
opposite angles indcribed in a circle are always have a sum of 180.
Parelle Lines Inside a Circle
they can be diffrent lengths, but will have congruent arcs.