Search results
Results from the WOW.Com Content Network
In geometry, a three-dimensional space (3D space, 3-space or, rarely, tri-dimensional space) is a mathematical space in which three values (coordinates) are required to determine the position of a point. Most commonly, it is the three-dimensional Euclidean space, that is, the Euclidean space of dimension three, which models physical space.
The fourth angle of a Lambert quadrilateral is an obtuse angle in elliptic geometry. The summit angles of a Saccheri quadrilateral are obtuse in elliptic geometry. The sum of the measures of the angles of any triangle is greater than 180° if the geometry is elliptic. That is, the defect of a triangle is negative. [80]
Geometry (from Ancient Greek γεωμετρία (geōmetría) ' land measurement '; from γῆ (gê) ' earth, land ' and μέτρον (métron) ' a measure ') [1] is a branch of mathematics concerned with properties of space such as the distance, shape, size, and relative position of figures. [2]
"Angle" also denotes the angular sector, the infinite region of the plane bounded by the sides of an angle. [2] [3] [a] Angle of rotation is a measure conventionally defined as the ratio of a circular arc length to its radius, and may be a negative number. In the case of an ordinary angle, the arc is centered at the vertex and delimited by the ...
The solid angle of a sphere measured from any point in its interior is 4 π sr. The solid angle subtended at the center of a cube by one of its faces is one-sixth of that, or 2 π /3 sr. The solid angle subtended at the corner of a cube (an octant) or spanned by a spherical octant is π /2 sr, one-eight of the solid angle of a sphere. [1]
the azimuthal angle φ, which is the angle of rotation of the radial line around the polar axis. [b] (See graphic regarding the "physics convention".) Once the radius is fixed, the three coordinates (r, θ, φ), known as a 3-tuple, provide a coordinate system on a sphere, typically called the spherical polar coordinates.
To produce accurate principal vectors in computer arithmetic for the full range of the principal angles, the combined technique [10] first compute all principal angles and vectors using the classical cosine-based approach, and then recomputes the principal angles smaller than π /4 and the corresponding principal vectors using the sine-based ...
Since no triangle can have two obtuse angles, γ is an acute angle and the solution γ = arcsin D is unique. If b < c, the angle γ may be acute: γ = arcsin D or obtuse: γ ′ = 180° − γ. The figure on right shows the point C, the side b and the angle γ as the first solution, and the point C ′, side b ′ and the angle γ ′ as the ...