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15 Cards in this Set
- Front
- Back
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What is a circle? |
A set of points that are equidistant from the center |
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A line segment from the center of a circle to a point on the circle |
radius |
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Two points on the circle connected by a line segment |
chord |
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A line segment that passes through the middle of a circle, also the longest chord |
diameter |
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What is the diameter's relationship to the radius? |
diameter = radius x 2 |
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What is a portion of the circle? |
An Arc |
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What is the distance around a circle? |
Circumference (perimeter) |
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Circumference of a circle = __ or __ |
2πr πd |
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Approximation of π |
3.14 22 / 7 |
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On the GRE π can be approximated to __ in some cases |
3 |
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Area of a circle = |
πr^2
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Arc length formula |
(x / 360) (2πr) |
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What is a sector? |
A piece of the circle (like pie) |
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Sector length formula |
(x / 360) (πr^2) |
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Area of sector, r = 6 angle = 160 degrees |
(160 / 360) (π6^2) (4 / 9) (36π) = (4 x 4π) 16π |
