Geometry › Circles

Teacher info
An intro to circles, radii, diameters, and chords
CCSS.MATH.CONTENT.HSG.CO.A.1
Know precise definitions of angle, circle, perpendicular line, parallel line, and line segment, based on the undefined notions of point, line, distance along a line, and distance around a circular arc.

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https://schoolyourself.org/page/lti/sy/geometry/circles
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The mathematics of lines, shapes, and angles. Essential stuff for describing the world around you.
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Lines and angles
Related angles
Triangles
Triangle congruence and similarity
Polygons and quadrilaterals
Area of polygons
The Pythagorean theorem
Circles, ellipses, and their areas
Circles
An intro to circles, radii, diameters, and chords
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Circumference and Pi
Find the distance around a circle (and then eat some pi)
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Size of the Earth
Use shadows to measure the Earth's circumference!
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Ellipses
What you get when you "stretch" a circle
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Area of a circle
Using circumference to find a circle's area
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Cavalieri's principle
Comparing shapes to find areas of the unusual ones
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Ellipse area
Calculate how many people can fit on the Ellipse in DC
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Areas of complex shapes
Add and subtract the ares of simpler shapes!
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Angles in circles
Lines in circles
Volume
Surface area
Transformations
Geometric optics