How Eratosthenes
Calculated the Circumference of the Earth |
While Eratosthenes was not the first to estimate the circumference
of the earth, his was the most accurate of the ancient estimates. Here
is how he did it.
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Perpendicular Bisector of a Chord |
A chord is a line segment with end points on a circle. When we
construct a perpendicular bisector of a chord, we create a figure with
interesting properties.
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Geometry and Numbers |
In ancient Greece nearly all math had roots in geometry. They even did multiplication
geometrically.
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The Kite |
The kite is a figure with many interesting properties. Begin exploring the
kite here.
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Properties of Right Triangles Incribed in Circles |
There are several interesting relationships between right triangles and their circumscribing circle.
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Drawing an ellipse given two circles with the same center. |
An ellipse can be outlined using two circles with the same center.
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Constructing an Ellipse Given a Circle and Inscribed Rectangle. |
An ellipse can be outlined using a circle and a rectangle inscribed in the circle.
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Geometric Nets
| A 'net' is a two dimensional (flat) figure that can be folded into a three dimensional geometric
shape. You can use these nets to build your own geometric shapes. For best results, print these on card stock. |