Symmetry is defined as portions that are the same around a fixed central point. Radial symmetry is symmetry around a central axis. Bilateral symmetry is symmetry about the two halves around a fixed point.
Radial symmetry appears in nature and man-made objects. A simple way to tell if an object has this form of symmetry is to draw several straight lines that cut through the center. If the object is the same on both sides of each line, then this object has radial symmetry. Examples of radial symmetry include some flowers and a circle that is one color.
Bilateral symmetry is also referred to as left-right or reflection symmetry. Like radial symmetry, it also occurs in nature and man-made objects. Checking for this form of symmetry can be done by drawing a line down the center of the object and checking to see if the right and left sides are the same. Examples of this form of symmetry include butterflies and cubes that are a single color.
There are other forms of symmetry, including rotational and translational. Rotational symmetry refers to an object that can be turned to some degree less than a full turn and appear the same. Translational symmetry refers to a pattern that repeats in intervals.