Analysis of information sources in references of the Wikipedia article "Angle" in English language version.
A plane angle is the inclination to one another of two lines in a plane which meet one another and do not lie in a straight line.
The latitude of a point on earth is defined as the conjugate of the angle between the point where the rotation axis pierces the celestial sphere (celestial pole) and the point where the local vertical pierces the same sphere (zenith).
α is a quantity symbol for plane angle.
The latitude of a point on earth is defined as the conjugate of the angle between the point where the rotation axis pierces the celestial sphere (celestial pole) and the point where the local vertical pierces the same sphere (zenith).