That line is called a "Diameter".
diameter
great circle
It is called a great circle. The equator is an example.
equator
The Equator...
prime merideane and equator The equator divides the earth into two equal halves.
equator
an equator
The other name for the line of symmetry of a circle is the diameter. The diameter of a circle is a line segment that passes through the center of the circle and has endpoints on the circle itself. It divides the circle into two equal halves, making it a line of symmetry. This means that if you were to fold the circle along the diameter, both halves would perfectly overlap.
You are drawing a line which divides the angle into 2 equal parts (halves).
A line segment that divides a circle in two is a chord.If the two parts of the circle are equal, the line segment is a diameter.See 'The Parts of the Circle' in Sources and related links, below.
A line passing through the center and crossing the circle.