How do you find the magnitude of a vector

The magnitude of a vector can be considered as the length of the vector. If you've been given a vector in terms of two perpendicular components (such as x,y or i,j) you can use pythagoras' theorem to find the length of the vector, as this will be the hypotenuse of the triangle.

For example if you have the vector v = 3i+4j, then the magnitude of v will be (3^2 + 4^2)^0.5, so v = 5