LAKE BRANTLEY
HIGH SCHOOL
Measures of Circles
Two-Dimensional
Student need to know...
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Circumference, arc lenght, and areas of circles and sectors.
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The benchmark will be assessed using MC (Multiple Choice) and FR (Fill in Response) items.
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All angle measurements will be in degrees.
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Formal or informal proofs completions may be required.
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Items may include references to circumference, radius, diameter, arc, arc length, chord, secant, tangent and concentric circles.
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Items may include central angles, inscribed angles and intersections of secants and tangents.
Example One
Allison created an embroidery design of a stylized star emblem. The perimeter of the design is made by alternating semicircle and quarter-circle arcs. Each arc is formed from a circle with a 2½-inch diameter. There are 4 semicircle and 4 quarter-circle arcs, as shown in the diagram below.
To the nearest whole inch, what is the perimeter of Allison's design?
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15 inches
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20 inches
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24 inches
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31 inches
Example Two
Kayla inscribed kite ABCD in a circle, as shown below.
If the measure of arc ADC is 255° in Kayla's design, what is the measure, in degrees, of ∠ADC?
Circle Basics
Area of a Circle
Concentric Circles
Arc Measure & Arc Lenght
Chord Properties
Central & Inscribed
Secants and Tangents
