Draw a
sketch showing the aircraft at its first position due North
of the VOR (360ºrdl). It is tracking 255º to its second position on the
330ºrdl. Consider the triangle made up by the aircraft's first position, the
aircraft's second position and the VOR. The angles of this triangle are:
At the aircraft's first position: 255º - 180º = 75º
At the VOR: 360º - 330º = 30º
The third angle, at the aircraft's second position, is: 180º - (75º + 30º) =
75º.
This is an isosceles triangle and the two sides which are equal are the ones
from the VOR to the aircraft's two positions.