If the x-coordinate of a point `P` on the join of `Q(2,2,1)a n dR(5,1,-2)i s4,` then find its `z-` coordinate.

Explanation

To solve the problem step by step, we can follow these instructions:

### Step 1: Identify the coordinates of points Q and R
The coordinates of point Q are \( Q(2, 2, 1) \) and the coordinates of point R are \( R(5, 1, -2) \).

### Step 2: Find the direction ratios of the line QR
The direction ratios can be calculated as follows:
- For x-coordinate: \( 5 - 2 = 3 \)
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