Answer:

A parabola is the shape of the graph y = x² , and of any quadratic function. It is the approximate path followed by any projectile in flights such as a shell, a ball or a stone. It has the property that when used as a reflector it concentrates a parallel beam of light or radio waves to a single point, the focus.

This fact is used in the design of telescopes and television aerials for sending and receiving messages from satellites. The shape taken up by the supporting cables of a suspension bridge is parabolic, and some modern motorway bridges have parabolic arches.

A parabola may also be expressed as a conic section with an eccentricity of 1. As a consequence of this, all parabolas are similar.

A parabola can also be obtained as the limit of a sequence of ellipses where one focus is kept fixed as the other is allowed to move arbitrarily far away in one direction. In this sense, a parabola may be considered an ellipse that has one focus at infinity. The parabola is an inverse transform of a cardioid.