Using vectors, find the area of the triangle with vertices A (1, 1, 2), B (2, 3, 5) and C (1, 5, 5).

Explanation

To find the area of the triangle with vertices A(1, 1, 2), B(2, 3, 5), and C(1, 5, 5) using vectors, we can follow these steps:

### Step 1: Define the position vectors
Let:
- Position vector of A, **A** = \( \mathbf{i} + \mathbf{j} + 2\mathbf{k} \)
- Position vector of B, **B** = \( 2\mathbf{i} + 3\mathbf{j} + 5\mathbf{k} \)
- Position vector of C, **C** = \( \mathbf{i} + 5\mathbf{j} + 5\mathbf{k} \)

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