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Warm-Up. Find the area of the shaded region. Diameter = 8 inches. Geometry 11-2 and 11-3. Arcs. Definition. A central angle is an angle whose vertex is the center of a circle. An arc is the distance between two points on a circle. central angle: x arc: AC. Types of Arcs.
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Warm-Up • Find the area of the shaded region. Diameter = 8 inches
Definition • A central angleis an angle whose vertex is the center of a circle. • An arcis the distance between two points on a circle. central angle: x arc: AC
Types of Arcs • Minor arc: needs only two letters to name it • The measure of the arc is the same as the measure of the angle • Major arc: needs three letters to name it -more than half of the circle -measure = 360 - x Minor arc Major arc
Example Find mKLF.
Definition A sector area of a circle is the area of a shaded portion of the cirlce. Sector Area = (area of circle) x (fraction of circle shaded)
Example • Find the area of the shaded sector JGH.
Definition An arc length of a circle is the distance around a circle between two points. Arc length= (circumference of circle) x (fraction of circle)
Example • Find the arc length of FG.
Example • Richard is going to build a fence around a portion of his circular garden. How many feet of fence will Richard need to complete the job? 18 ft