Three vectors `vecA,vecB` and `vecC` are such that `vecA=vecB+vecC` and their magnitudes are in ratio 5:4:3 respectively. Find angle between vector `vecA` and `vecB`

Explanation

To solve the problem, we need to find the angle between vector \(\vec{A}\) and vector \(\vec{B}\) given that \(\vec{A} = \vec{B} + \vec{C}\) and their magnitudes are in the ratio 5:4:3.

### Step-by-Step Solution:

1. **Define the Magnitudes**:
Let the magnitudes of the vectors be:
\[
|\vec{A}| = 5x, \quad |\vec{B}| = 4x, \quad |\vec{C}| = 3x
...