This is not a true Euclidean construction as defined in Constructions - Tools and Rules but a practical way to draw an ellipse when mathematical precision is not so important, but if you are careful, you can get fairly close. It is sometimes called the "Gardener's Ellipse", because it works well on a large scale, using rope and stakes, to lay out elliptical flower beds in formal gardens.

You can also calculate the positions of the focus points. See Foci of an Ellipse.

After doing this	Your work should look like this
Start with the height and width of the desired ellipse. The two lines are the major and minor axes of the ellipse. The major axis is the longest one.
1.  With the compass point on the center, set the compass width to half the width (major axis) of the desired ellipse. (This is called the ellipse semimajor axis).
2.  Move the compass point to one end of the minor axis of the desired ellipse and draw two arcs across the major axis.
3.  Where these arcs cross the major axis are the foci of the ellipse. Label them F1, F2.
4.  Put a pin in each end of the major axis (they will be moved later), and tie a string to them so that the string between them is taut. The best way to do this is to push the pin through the string itself if possible, rather than tying a knot.
5.  Leaving the string attached, move the pins to the focus points F1, F2. Put a pencil point against the string and pull the string taut with the pencil.
6.  Keeping the string taut, move the pencil in a large arc. The pencil will draw out the desired ellipse. To avoid the string catching on the pins, you may find it better to draw the upper and lower halves of the ellipse separately.
7.  Done. The ellipse will pass through the four initial points defining the ends of the major and minor axes.

Constructions pages on this site

Lines

• Introduction to constructions
• List of printable constructions worksheets
• Copy a line segment
• Perpendicular bisector of a line segment
• Perpendicular from a line at a point
• Perpendicular from a line through a point
• Perpendicular from endpoint of a ray
• Divide a segment into n equal parts
• Parallel line through a point (angle copy method)
• Parallel line through a point (rhombus method)

Angles

• Bisecting an angle
• Copy an angle
• Construct a 30° angle
• Construct a 45° angle
• Construct a 60° angle
• Construct a 90° angle (right angle)
• Constructing  75°  105°  120°  135°  150° angles and more

Triangles

• Copy a triangle
• Isosceles triangle, given base and side
• Isosceles triangle, given base and altitude
• Equilateral triangle
• Triangle medians
• 30-60-90 triangle, given the hypotenuse
• Triangle, given 3 sides (sss)
• Triangle, given one side and adjacent angles (asa)
• Triangle, given two sides and included angle (sas)
• Incircle of a triangle
• Circumcircle of a triangle

Triangle Centers

• Triangle incenter
• Triangle circumcenter
• Triangle orthocenter
• Triangle centroid

Circles, Arcs and Ellipses

• Finding the center of a circle
• Circle given 3 points
• Tangent at a point on the circle
• Tangents through an external point
• Focus points of a given ellipse

Polygons

• Hexagongiven one side
• Hexagon inscribed in a given circle
• Pentagon inscribed in a given circle

Non-Euclidean constructions

• Construct an ellipse with string and pins
• Find the center of a circle with any right-angled object