ROTATIONAL SYMMETRY Meaning and
Definition
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Rotational symmetry refers to a property exhibited by certain objects or shapes when they can be rotated by a certain angle and still maintain the same appearance. In other words, it is a type of symmetry that exists when an object can be rotated around a fixed point, known as the axis of rotation, and still appear identical at different positions throughout the rotation.
To demonstrate rotational symmetry, an object must have at least one axis of rotation, which can be any line passing through the object's center. The most common examples of rotational symmetric objects are circles and regular polygons, such as squares, equilateral triangles, and pentagons. These shapes possess an infinite number of rotational symmetries because they can be rotated by any angle and still look the same at different positions.
The degree of rotational symmetry refers to the number of distinct positions in which an object appears identical during a full rotation of 360 degrees. For example, a square possesses rotational symmetry of order 4 since it looks the same after rotating it by an angle of 90 degrees, 180 degrees, or 270 degrees. This is due to its four equal sides and four 90-degree angles.
In summary, rotational symmetry is a property that some objects hold when they can be rotated around a fixed point and maintain the same appearance in various positions. It is an essential concept in mathematics and geometry, helping to classify shapes and determine their symmetrical properties.
Etymology of ROTATIONAL SYMMETRY
The term "rotational symmetry" can be broken down into two parts: "rotation" and "symmetry".
The word "rotation" comes from the Latin word "rotare", meaning "to turn or revolve". It is derived from the Proto-Indo-European root "ret-", which also gave rise to words like "rotate" and "rotary".
The word "symmetry" comes from the Greek word "symmetria", meaning "agreement in dimensions, due proportion, arrangement". It is derived from "syn-" (together) and "metron" (measure).
Therefore, "rotational symmetry" refers to the symmetrical arrangement of an object or shape that remains unchanged or looks the same after being rotated around a fixed point (often a central axis or center of rotation). The term reflects the concepts of rotation and symmetry, combining their respective origins from Latin and Greek.
