Use "radius vector" in a sentence

1. ‘Apsidal motion is one of the classical diagnostics of stellar structure.’ ‘The angle through which the radius vector rotates in going between two consecutive apsides is called the Apsidal angle.’

2. ‘Apsidal motion is one of the classical diagnostics of stellar structure.’ ‘The angle through which the radius vector rotates in going between two consecutive apsides is called the Apsidal angle.’