From previous questions, we know that a vector is described by its magnitude and its direction. Let us better understand the direction of a vector mathematically.

By convention, the direction of a vector is measured by the angle the vector makes with the positive x-axis, in the anti-clockwise direction. From the figure, this is \(40^{\circ}\). This is just a convention, but, it is a convention that we will follow throughout the website.

Going in the anti-clockwise direction means that we will start from the +x-axis and move up to reach the vector, not down.