If two secants are drawn to a circle from an external point, then the product of the length of one secant segment and its external segment equals the product of the length of the other secant segment ...
IN modern treatises on crystallography, the crystal is imagined projected radially on the surface of a sphere, and the spherical triangles so obtained are dealt with by spherical trigonometry.
Some results have been hidden because they may be inaccessible to you
Show inaccessible results