Bearings are measured clockwise in degrees from this reference direction. Another unit of angle measure is the radian. I am sometimes tempted to use radians because a lot of software uses radians in trigonometric calculations, including Excel. However, most readers of this material are likely to be more comfortable with degrees . Knots just don't make sense on the highway.
Familiarity is everything.
In the discussions that follow we will be using spreadsheet templates for calculations. As mentioned, Excel, and most spreadsheet programs, perform their calculations using 'radians'. This means that when using trigonometric functions in spreadsheets, angles in degrees must first be converted into radians. Points are specified by a pair of numbers called the coordinates of the point. Nothing new here.