The equator, which is a line of latitude and divides the Earth into northern and southern hemispheres. And prime meridian, which is a line of longitude and divides the Earth into eastern and western hemispheres.
A chord is a straight line within a circle that divides the circle into two parts - these parts are called arcs. The diameter is a chord that runs through the centre of the circle and divides the circle into two equal parts.
* Equator; The line perpendicular to the axis of the earth bisecting it into two halves. * Latitudes; Horizontal lines parallel to the equator. * Longitudes; Verticle lines paralell to the earth's axis.