Diameter

In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. Geometry ( Greek γεωμετρία; geo = earth metria = measure is a part of Mathematics concerned with questions of size shape and relative position Circles are simple Shapes of Euclidean geometry consisting of those points in a plane which are at a constant Distance, called the In Geometry, a line segment is a part of a line that is bounded by two distinct end points, and contains every point on the line between its end points The diameters are the longest chords of the circle. A chord of a Curve is a geometric Line segment whose endpoints both lie on the curve The word "diameter" derives from Greek διάμετρος (diametros), "diagonal of a circle", from δια- (dia-), "across, through" + μέτρον (metron), "a measure"^[1]). Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly

In more modern usage, the length of a diameter is also called the diameter. In this sense one speaks of the diameter rather than a diameter, because all diameters of a circle have the same length, this being twice the radius. Circles are simple Shapes of Euclidean geometry consisting of those points in a plane which are at a constant Distance, called the Remote Authentication Dial In User Service ( RADIUS) is a networking protocol that provides centralized access authorization and accounting management for people or computers

For a convex shape in the plane, the diameter is defined to be the largest distance that can be formed between two opposite parallel lines tangent to its boundary, and the width is defined to be the smallest such distance. For a curve of constant width such as the Reuleaux triangle, the width and diameter are the same because all such pairs of parallel tangent lines have the same distance. In Geometry, a curve of constant width is a convex planar Shape whose width measured by the distance between two opposite parallellines touching its boundary A Reuleaux polygon is a Curve of constant width - that is a curve in which all diameters are the same length

The diameter of a connected graph is the distance between the two vertices which are furthest from each other. In Mathematics and Computer science, connectivity is one of the basic concepts of Graph theory. For other uses see Vertex. In Graph theory, a vertex (plural vertices) or node is the fundamental unit out The distance between two vertices a and b is the length of the shortest path connecting them (for the length of a path, see Graph theory). In Mathematics and Computer science, graph theory is the study of graphs: mathematical structures used to model pairwise relations between objects

The three definitions given above are special cases of a more general definition. The diameter of a subset of a metric space is the least upper bound of the distances between pairs of points in the subset. In Mathematics, a metric space is a set where a notion of Distance (called a metric) between elements of the set is defined So, if A is the subset, the diameter is

sup { d(x, y) | x, y ∈ A } .

In medical parlance the diameter of a lesion is the longest line segment whose endpoints are within the lesion. An idiom is a Phrase whose meaning cannot be deduced from the literal Definition, but refers instead to a figurative meaning that is known only A lesion is any abnormal tissue found on or in an organism usually damaged by disease or trauma

Diameter symbol

Sign ⌀ from Autocad drawing

The symbol or variable for diameter is similar in size and design to ø, the lowercase letter o with stroke. AutoCAD is a CAD (Computer Aided Design Software application for 2D and 3D Design and drafting, developed and sold by The musical instrument is spelled Cymbal. A symbol is something --- such as an object, Picture, written word a sound a piece A variable (ˈvɛərɪəbl is an Attribute of a physical or an abstract System which may change its Value while it is under Observation. The " Ø " ( minuscule: " ø " is a Vowel and a letter used in the Danish, Faroese and Norwegian Unicode provides character number 8960 (hexadecimal 2300) for the symbol, which can be encoded in HTML webpages as ⌀ or ⌀. In Computing, Unicode is an Industry standard allowing Computers to consistently represent and manipulate text expressed in most of the world's In Mathematics and Computer science, hexadecimal (also base -, hexa, or hex) is a Numeral system with a HTML, an initialism of HyperText Markup Language, is the predominant Markup language for Web pages It provides a means to describe the structure Proper display of this character, however, is unlikely in most situations, as most fonts do not have it included. In Typography, a typeface is a set of one or more Fonts designed with stylistic unity each comprising a coordinated set of Glyphs A typeface usually comprises (Your browser displays ⌀ in the current font. ) In most situations the letter ø is acceptable, obtained in Microsoft Windows by holding the [Alt] key down while entering 0 2 4 8 on the numeric keypad. Microsoft Windows is a series of Software Operating systems and Graphical user interfaces produced by Microsoft. A numeric keypad, or numpad for short is the small palm-sized seventeen key section of a Computer keyboard, usually on the very far right

The diameter symbol, ⌀, is distinct from the empty set symbol, ∅, and from an uppercase phi, Ø. In Mathematics, and more specifically Set theory, the empty set is the unique set having no ( Zero) members Phi (uppercase Φ, lowercase φ or ϕ) pronounced in modern Greek and as in English is the 21st letter of the Greek alphabet

The diameter also refers to the approximate size of the corner of a frame of any given object to the nearest flat surface it represents.

See also

• angular diameter
• hydraulic diameter
• caliper, micrometer, tools for measuring diameters
• Eratosthenes, who calculated the diameter of the Earth around 240 BC. The angular diameter of an object as seen from a given position is the "visual diameter" of the object measured as an angle The hydraulic diameter D_h, is a commonly used term when handling Flow in noncircular Tubes and channels A caliper ( British spelling also calliper) is a device used to measure the distance between two symmetrically opposing sides Eratosthenes of Cyrene ( Greek; 276 BC - 194 BC was a Greek Mathematician, Poet, athlete, Geographer and EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001
• Jung's theorem, an inequality relating the diameter to the radius of the smallest enclosing ball

References

External links

• (geometry) Diameter and many other circle properties defined With interactive applets