The magnitude of a vector A is represented using the modulus operator ie A. A unit vector is a vector whose magnitude is equal to 1. Magnitude And Direction Of A Vector Positive Numbers Absolute Value Directions Geometrically the magnitude of a vector corresponds to the length of the vector in space. . In 3-D the direction of a vector is defined by. Take the square root of the result. The Magnitude of a Vector Formula for n Dimensions. The magnitude of a vector formula is used to calculate the length of a vector and is denoted by v. This formula is derived from the. The Magnitude of a Vector in Two Dimensions. Firstly the magnitude is calculated for a vector when its final point is at origin 00 while in the other. The magnitude of a vector formula helps to summarize the numeric value for a given vector. For example the magnitude of the vector 34 is 5 because the square root of 3 squared plus 4.