If the magnitude of there vectors `vec X, vecY and vecZ` are 4, 3 and 5, respectively and `vecX+vecY=vecZ`, then calculate the angle between `vecY and vecZ`.

Explanation

To solve the problem, we need to find the angle between the vectors \(\vec{Y}\) and \(\vec{Z}\), given that \(\vec{X} + \vec{Y} = \vec{Z}\) and their magnitudes are as follows:

- Magnitude of \(\vec{X} = 4\)
- Magnitude of \(\vec{Y} = 3\)
- Magnitude of \(\vec{Z} = 5\)

### Step 1: Understand the relationship between the vectors
Since \(\vec{Z} = \vec{X} + \vec{Y}\), we can use the law of cosines to relate the magnitudes of these vectors.
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