Altern base, in trigonometry, is a term used in distinction from the true base. Thus, in oblique triangles, the true base is the sum of the sides, and then the difference of the sides is the altern base; or the true base is the difference of the sides, and then the sum of the side is the altern base.
This article incorporates content from the 1728 Cyclopaedia, a publication in the public
domain.
