How do you use vector components to find the magnitude?
To find the magnitude of a vector using its components you use Pitagora´s Theorem.
Consider in 2 dimensions a vector
The magnitude of this vector (or its length in geometrical sense) is given using Pitagora's Theorem, as:
The same thing applies in 3 dimensions, the only thing is to include the third component.
So if the vector is now given as:
The magnitude will be: