An angle between two vectors $\theta$ is the angle from initial point of first vector to any point to where the second vector rotates from the common vertex. 

If $\vec{A}$ and $\vec{B}$ are two given vectors where $\vec{A}$ = a1i + b1j + c1k and $\vec{B}$ = a2i + b2j + c2k then the angle between two vectors $\theta$ is given by
Angle between two vectors Calculator
Angle between two vectors Calculator calculates the angle between two given vectors if the magnitudes of given vectors a1, b1, c1and a2, b2, c2 are entered in the blocks provided.
Here are some steps to find the angle between two vectors
Step 1 : Read the given problem and observe whether vectors are of the form
A = a1 i + b1 j + c1 k
B = a2 i + b2 j + c2 k
Where a1, b1, c1 and a2, b2 and c2 are magnitudes of given components.

Step 2 : Find the value of dot product A.B given as
A.B = a1b1 + a2b2 + a3b3
The values of |A| and |B| as
|A| = $\sqrt{a_{1}^{2} + b_{1}^{2} + c_{1}^{2}}$
|B| = $\sqrt{a_{2}^{2} + b_{2}^{2} + c_{2}^{2}}$

Step 3 : Find the value of cos $\theta$ using formula
cos $\theta$ = $\frac{A.B}{|A|.|B|}$
and from this get the values of $\theta$ as
$\theta$ = cos-1 $\frac{A.B}{|A||B|}$.