A triangle having two of its sides equal
Related Terms 
HYPOTENUSE
The side of a plane right triangle opposite the right angle; the longest side of a plane right triangle

AGETON
A divided triangle method of sight reduction in which a perpendicular is dropped from the GP of the body to the meridian of the observer

ALTITUDE AZIMUTH
An azimuth determined by solution of the naviga tional triangle with altitude, declination, and latitude given. A time azimuth is computed with meridian angle, declination, and latitude given. A time and altitude azimuth is computed with meridian angle, declination, and altitude given

ASTRONOMICAL TRIANGLE
The navigational triangle either terrestrial or celestial, used in the solution of celestial observations.

CELESTIAL TRIANGLE
A spherical triangle on the celestial sphere, especially the navigational triangle

COSECANT
The ratio of the hypotenuse of a plane right triangle to the side opposite one of the acute angles o

COCKED HAT
Error triangle formed by lines of position which do not cross at a common point

COTANGENT
The ratio of the shorter side adjacent to an acute angle of a plane right triangle to the side opposit

COSINE
The ratio of the side adjacent to an acute angle of a plane right triangle to the hypotenuse. The expression NATURAL COSINE is sometimes used to distinguish the cosine from its logarithm (called LOGARITHMIC COSINE).

EQUILATERAL TRIANGLE
A triangle having all of its sides equal. An equilateral triangle is necessarily equiangular
