Search results
Results from the WOW.Com Content Network
Bahasa Indonesia: Gambar 2 - Sistem koordinat Kartesius disertai lingkaran merah yang berjari-jari 2 yang berpusat pada titik asal (0,0). Persamaan lingkaran merah ini adalah x² + y² = 4. Persamaan lingkaran merah ini adalah x² + y² = 4.
In this context, a diameter is any chord which passes through the conic's centre. A diameter of an ellipse is any line passing through the centre of the ellipse. [7] Half of any such diameter may be called a semidiameter, although this term is most often a synonym for the radius of a circle or sphere. [8] The longest diameter is called the ...
Semicircle: one of the two possible arcs determined by the endpoints of a diameter, taking its midpoint as centre. In non-technical common usage it may mean the interior of the two-dimensional region bounded by a diameter and one of its arcs, that is technically called a half-disc. A half-disc is a special case of a segment, namely the largest one.
PR is the diameter of a circle centered on O; its radius AO is the arithmetic mean of a and b. Using the geometric mean theorem, triangle PGR's altitude GQ is the geometric mean. For any ratio a:b, AO ≥ GQ. A semicircle can be used to construct the arithmetic and geometric means of two lengths using straight-edge and compass.
This is equivalent to the above definition of the 2D mean diameter. However, for historical reasons, the hydraulic radius is defined as the cross-sectional area of a pipe A , divided by its wetted perimeter P , which leads to D H = 4 R H {\displaystyle D_{\text{H}}=4R_{\text{H}}} , and the hydraulic radius is half of the 2D mean radius.
This is related to the angular diameter distance, which is the distance an object is calculated to be at from and , assuming the Universe is Euclidean. The Mattig relation yields the angular-diameter distance, d A {\displaystyle d_{A}} , as a function of redshift z for a universe with Ω Λ = 0.
By 1900, various estimates of mercury atom diameter averaged around 275±20 pm [7] (modern estimates give 300±10 pm, see below). In 1920, shortly after it had become possible to determine the sizes of atoms using X-ray crystallography , it was suggested that all atoms of the same element have the same radii. [ 11 ]
In geometry, a disk (also spelled disc) [1] is the region in a plane bounded by a circle.A disk is said to be closed if it contains the circle that constitutes its boundary, and open if it does not.