Ellipse << ih LIHPS >> is a geometric figure with the shape of a flattened hoop. In geometric terms, an ellipse is one of the conic sections (see Cone).
An ellipse may be drawn with an ellipsograph (elliptic compass). But the simplest method to draw an ellipse is to fasten the ends of a string at two points, called the foci. The string must be longer than the distance between the foci. Hold a pencil upright against the string so the string is stretched tight at all times. Draw half the ellipse; then lift the pencil and move the string to the other side of the pins to draw the second half. The diameter passing through the foci is called the major axis. The diameter running perpendicular (at right angles) to the major axis is the minor axis. To find the area of an ellipse, multiply half the length of the major axis by half that of the minor axis. Multiply the result by pi, which has an approximate value of 3.14159.
The ellipse was used by the German astronomer Johannes Kepler in the 1600’s to describe the orbits of the planets of the solar system. Kepler discovered that each of the planets follows an elliptical path that has the sun as one of its foci.
