Section 1.7: Circles
A locus is a set of points that meet a given condition. The definition of a circle locus of points a given distance from a given point in a 2-dimensional plane. The given distance is the radius and the given point is the center of the circle. In 3-dimensions (space), we would define a sphere as the set of points in space a given distance from a given point
A central angle is an angle whose vertex is on the center of the circle and whose endpoints are on the circle. The endpoints on the circle are also the endpoints for the angle's intercepted arc. The angle measure of the central angle is congruent to the measure of the intercepted arc which is an important fact when finding missing arcs or central angles
A chord is a line segment whose endpoints are on a circle. If a chord passes through the center of the circle, it is called a diameter. Two important facts about a circle chord are that (1) the perpendicular bisector of any chord passes through the center of a circle and (2) congruent chords are the same distance (equidistant) from the center of the circle.
A tangent intersects a circle in exactly one point. When two segments are drawn tangent to a circle from the same point outside the circle, the segments are congruent. The extension problem of this topic is a belt and gear problem which asks for the length of belt required to fit around two gears. Topics related to circle radii include inscribed circles andradii to tangents.
A central angle is an angle whose vertex is on the center of the circle and whose endpoints are on the circle. The endpoints on the circle are also the endpoints for the angle's intercepted arc. The angle measure of the central angle is congruent to the measure of the intercepted arc which is an important fact when finding missing arcs or central angles
A chord is a line segment whose endpoints are on a circle. If a chord passes through the center of the circle, it is called a diameter. Two important facts about a circle chord are that (1) the perpendicular bisector of any chord passes through the center of a circle and (2) congruent chords are the same distance (equidistant) from the center of the circle.
A tangent intersects a circle in exactly one point. When two segments are drawn tangent to a circle from the same point outside the circle, the segments are congruent. The extension problem of this topic is a belt and gear problem which asks for the length of belt required to fit around two gears. Topics related to circle radii include inscribed circles andradii to tangents.
Notes and Powerpoints
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