Solid angle orientation formula_9, and distance from the viewer as: where the surface area of a sphere is . The solid angle of a cone with its apex at the apex of the solid angle, and with apex angle 2, is the area of a spherical cap on a unit sphere For small such that , this reduces to the area of a circle . The above is found by computing the following double integral using the unit surface element in spherical coordinates: This formula can also be derived without the use of calculus. Over 2200 years ago Archimedes proved that the
Solid surface manufactured in sheet form for fabrication into finished countertops, solid surface can also be cast into a variety of shapes, including sinks, shower pans and bathtubs. Sheet goods can also be heated and bent into three-dimensional shapes using a process called thermoforming, which adds to the versatility of the product. Color and design flexibility are key factors when choosing engineered composites over natural stone. In a residential setting, solid surface can be used as kitchen countertops, bathroom vanity tops, and shower and tub surrounds. Countertop fabricators typically join solid surface sheets into desired shapes using a two-part adhesive, after which