Solid angle of its faces is one-sixth of that, or sr. Solid angles can also be measured in square degrees (1 sr = () square degrees), in square minutes and square seconds, or in fractions of the sphere (1 sr = fractional area), also known as spat (1 sp = 4 sr). In spherical coordinates there is a formula for the differential, where is the colatitude (angle from the North pole) and is the longitude. The solid angle for an arbitrary oriented surface S subtended at a point P is equal to the solid angle of the projection of the surface S
Solid surface wall cladding, because its seamless properties eliminate gaps and crevices that harbor harmful bacteria. Solid surface is manufactured by mixing acrylic, epoxide or polyester resin with powdered bauxite filler and pigments. The material chemically cures and is heated to 60°C or more. Cured material is then cut in sheets or shapes and sanded on one or both sides depending the brand used. Sometimes the material is brought to 160°C and cooled, to improve its heat resistance. Acrylic-modified polyester solid surface can be mixed one sheet at a time using different formulations, effects and appearances. Acrylic-modified polyester solid surface can be