Final answer:
A VOR is typically much more precise than 10 degrees, generally within 1 degree, so the statement about VOR accuracy is false. Additionally, knowing only the angles of two vectors is insufficient to determine the angle of their resultant addition vector; magnitudes are also needed.
Step-by-step explanation:
The accuracy of a VOR (VHF Omnidirectional Range) is not as low as 10 degrees; under normal operating conditions, it is usually much more precise. The statement that a VOR can be considered accurate to 10 degrees is generally false. A VOR's accuracy is often within 1 degree of the selected course when the equipment is functioning correctly. Hence, for navigation purposes, especially in aviation where VOR systems are commonly used, relying on an accuracy within 10 degrees would not be acceptable.
Regarding vector addition, it is true that if only the angles of two vectors are known, one cannot find the exact angle of their resultant addition vector without additional information such as their magnitudes. The angle of the resultant vector depends on both the angles and the magnitudes of the original vectors.