| Construction Algorithm |
| 1 |
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Construct a line AC as a given diagonal of the parallelogram. |
| 2 |
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Construct M as a midpoint of the diagonal AC. |
| 3 |
|
Construct a free line through M. |
| 4 |
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Construct a point B on the free line. |
| 5 |
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Construct a circle centered at M and has a circumference point B at the free line. |
| 6 |
|
Generate the intersection points between the circle and the free line to find the fourth vertex D of the parallelogram. |
| 7 |
 |
Join up the four points A, B, C, and D to get the required parallelogram. |
| 8 |
 |
Switch to Move Mode. Pick a free element. Move it around to check your construction. |
| Construction Theorem |
| A parallelogram is a quadrilateral, in which diagonals bisect each other. |