Final answer:
The direction angle of a vector is calculated using trigonometric relationships if its components are known or measured with a protractor in relation to a reference axis. Bearings and compass directions also provide means to express vector directions.
Step-by-step explanation:
The direction angle of a vector can be determined in various ways depending on the context and the given information. If the scalar components (Ax and Ay) of a vector are known, the magnitude (A) and direction angle can be calculated using trigonometric relationships, as they form a right triangle with the vector. The direction angle is measured counterclockwise from the positive x-axis to the vector. In practical situations, a ruler and a protractor can be used to measure the magnitude and the direction of a vector, respectively.
Bearings are another method to express the direction of a vector. A bearing provides direction relative to a fixed point, usually North, and is stated as a three-digit number representing the clockwise angle from North. Additionally, compass directions such as 'North 50° West' can be used to indicate the direction of vectors not aligned with cardinal points.