How do you draw an elliptical circle?


Quick Answer

One easy method of drawing an elliptical circle includes finding two focus points, attaching a piece of string between them and running a pencil in all directions as far as the string allows. This is not technically considered a true Euclidean construction, but it is a practical and quick way to draw an ellipse with accurate dimensions.

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How do you draw an elliptical circle?
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Full Answer

The width of an ellipse is called the major axis. The height of an ellipse is called the minor axis. This construction is best done on graph paper. First, set a compass to half of the desired major axis length. Place the point of the compass in the center of the page and mark the distance in each direction. Then, do the same with half the distance of the minor axis by placing the compass point in the center and marking two points up and down. Reconfigure the compass length back to the length of half the major axis. Place the point of the compass at one end of the minor axis and mark a point on each side of the major axis. These two points are known as the focal points.

Place a push pin at each end of the major axis and tie a string between them so that it is taut. Then, leaving the string attached, relocate the push pins at each focal point. As the distance between the two focal points is shorter than the distance of the major axis, the string is no longer taut. Place a pencil point against the string and pull the string taut with the pencil. Keeping the string taut at all times, move the pencil in a wide arc. This draws an ellipse.

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