With this playground you can verify some fundamental geometric theorems :
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Demo 2: In a triangle the three medians intersect at the same point, the center of gravity.
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Demo 3: In a triangle the three heights intersect at the same point, the orthocenter.
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Demo 4: In a triangle the three bisectors intersect at the same point, the center of the inscribed circle.
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Demo 5: The three circles intersect at the same point, the Miquel point.
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Demo 6: In a triangle, the three mediators intersect at the same point, the center of the circumscribed circle.
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Demo 7: The middle sides of any quadrilateral form the Varignon parallelogram.
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Demo 8: Construction of a pentagon inscribed in a circle:
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Demo 9: In a triangle, the triangle formed by the midpoints of the sides has its sides parallel to the original triangle.
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Demo 10: The intersections of the four circles are cocyclical.
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Demo 11: The medians of the triangle (green) are the bisectors of the triangle (red) joining the middle of the sides.
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Demo 12: The perpendiculars to the sides of a quadrilateral passing through the middle of the opposite side intersect at the same point.
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Demo 15: Napoleon's theorem.
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Demo 16 : Desargues's theorem.
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Demo 17 : Pappus's theorem.
- Demo 18 : Locus of points equidistant from point and circle
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Demo 19 : Ornemental construction
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Demo 20 : Area comparison
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Demo 21 : Locus of the middle of a ladder sliding to the ground
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Clone or download the directory .
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Open
geom.htmlin your browser. -
Build your own problem, or drop one of the json files to the workspace.
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A construction always starts with some points. From these you can build other objects : segments, lines, circles, etc.
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To add an element to the problem, click on the corresponding icon in the toolbox, then follow the instructions in the bottom status line.
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A free point is represented by a circle. It can be moved with the mouse.
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A constructed point is represented by a disk. It cannot be moved by itself.
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A constrained point is represented by a square. It can be moved along its path.
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To select an element, click on its name in the list. It will be displayed hilited.
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To unselect an element, click again on its name.
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To change the color of an element, click on its colored square and choose another color in the palette.
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To scroll the list, use the up and down keys from the keyboard.