Meaning and Definition of Diameter

Definition of diameter

In geometry, the diameter is the straight line which passes through the Center and joining two opposite points, either in a circle, in a closed curve or on a spherical surface. All diameter will divide the circle in question in two semicircles.
The relationship between the length of the circumference and its diameter is a constant which is called pi and is written in the following way: π. anyway, may also be that we find phi, pronounced fi. The most popular abbreviation of diameter turns out to be day or d. Meanwhile, its value is approximately 355/113, which is the same to say 3,14159.
In the field of engineering and other technical areas, the symbol or variable for the diameter is similar both in size and design to or, although it is important to not confuse this symbol with the of the empty set, which is similar but in the case of this last is written in capital letter while diameter is lowercase.
On the other hand, the angular diameter is the apparent size of the equatorial diameter of a celestial body expressed as in angle and assuming the observer at the apex. In the case of the Sun, Moon and planets the measurement of the angular diameter will be known through optical or micrometric, procedures as, in the case of the brightest stars angular diameter can know it from interferometric procedures, which involve interference.
And in hydraulics, the branch of physics that deals with the study of the mechanical properties of fluids, hydraulic diameter turns out to be a fairly common concept in the event that it intervene in fluids of non-circular tubes and channels. Based on this concept, it is possible to learn more about the behavior of the flow in the same manner as if it were a pipe of circular section.