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“I Guess you can Get anything on EBAY”

Geometry PropertiesCatherine Haight

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• All of the following Geometric properties were simply found by searching on EBay.

• I chose eBay as the unifying theme for my example project because they say you can find it all on eBay.

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Parallel Lines cut by a Transversal•Parallel lines are lines in the same plane that do not intersect.•A transversal is a line diagonal that intersects the parallel lines•This photo from came up in the search for parallel•Theorems like the Same Side Interior Angles (3-2), the Corresponding Angle Postulate (3-1), and the Alternate Interior Angle (3-1) can all be demonstrated here .

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Congruent Triangles•The picture is of a Rubik's Triangle being sold on eBay. Every face of the tetrahedron are congruent triangles . •Each triangle on the surface of the face are also congruent triangles.• The Side-Side-Side Triangle congruence Postulate (4-1) can be demonstrated on each face of the toy.• These triangles are all equilateral and equiangular.

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Triangle Inscribedin Circle•A triangle is inscribed in a circle when only the three vertices of the triangle intersect the circle.•The circumcenter of a triangle is created at the intersection of the three perpendicular bisectors of the triangle.•The Circumcenter is the center of the circle and the radius is the length of the line from this point to a vertex.•This photo is an advertisement on eBay for a charm that can be bought.

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Regular Polygon > 4 sides

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Rectangle, Rhombus, Square

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Similar Triangles

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Circle w/diameter and radius

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Non-Congruent Polygons w/equal Areas

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Cylinder vs. Cone

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Interesting Geometry

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Analysis : Similar Triangles•These Triangles are similar by AA Similarity. ABC ~ DEF•This means that the corresponding sides are proportional.

A

BC

D

E

F

FD

CA

EF

BC

DE

AB ==

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Analysis: Cones vs. Cylinders

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Analysis: Non-congruent Polygons w/Equal Area•Area of Square

•Area of Triangle

•Area of Parallelogram

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Geometry can be bought on eBay

This web-quest and project has been enjoyable and informative. It only takes looking at the world around you to realize that geometric properties exist everywhere. I went to eBay and did searches for products with key words. Then browsed through the pictures of the product looking for the specific properties. I didn’t find any difficult to find but the easiest to find was anything that had triangles.