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For example, assuming the Earth is a sphere of radius 6371 km, the surface area of the arctic (north of the Arctic Circle, at latitude 66.56° as of August 2016 [7]) is 2π ⋅ 6371 2 | sin 90° − sin 66.56° | = 21.04 million km 2 (8.12 million sq mi), or 0.5 ⋅ | sin 90° − sin 66.56° | = 4.125% of the total surface area of the Earth ...
In this context the projection is called the equal-area hemispherical projection. The Schmidt net is often used to sketch out the Lambert azimuthal projection for these purposes. [ 1 ] Conversely, the Wulff net ("equal-angle projection") is used to plot crystallographic axes and faces.
A sphere of radius r has surface area 4πr 2.. The surface area (symbol A) of a solid object is a measure of the total area that the surface of the object occupies. [1] The mathematical definition of surface area in the presence of curved surfaces is considerably more involved than the definition of arc length of one-dimensional curves, or of the surface area for polyhedra (i.e., objects with ...
The solid angle of an object that is very far away is roughly proportional to the ratio of area to squared distance. Here "area" means the area of the object when projected along the viewing direction. Any area on a sphere which is equal in area to the square of its radius, when observed from its center, subtends precisely one steradian.
More generally, the lateral surface area of a prism is the sum of the areas of the sides of the prism. [1] This lateral surface area can be calculated by multiplying the perimeter of the base by the height of the prism. [2] For a right circular cylinder of radius r and height h, the lateral area is the area of the side surface of the cylinder ...
Northern Hemisphere: The half that lies north of the Equator. This hemisphere contains approximately 68% of Earth's landmass and is home to about 90% of the global population. [4] It includes North America, Europe, Asia, and most of Africa. Southern Hemisphere: The half that lies south of the Equator. It contains approximately 32% of Earth's ...
The area density (also known as areal density, surface density, superficial density, areic density, mass thickness, column density, or density thickness) of a two-dimensional object is calculated as the mass per unit area. The SI derived unit is the "kilogram per square metre" (kg·m −2).
which is the standard formula for the area of a surface described this way. One can recognize the vector in the second-last line above as the normal vector to the surface. Because of the presence of the cross product, the above formulas only work for surfaces embedded in three-dimensional space.