How to find the distance using dot product from point $A$ to the line through $B$ and $C$?

The points are $A = (2, -6, 1)$, $B = (3, 4, -2)$ and $C = (7, -1, 5)$.

I have tried this method: $$d=\frac{||BC \times BA||}{||BC||}$$

Please tell me how to find the distance using dot product.


Question: How do I delete nodes older than X days?
Answer: You could use the Auto Expire module.


  This module allows site administrators to set expiration times for content types.
  
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  Before a node is expired a warning message is sent to the user that created that node. If the user has the proper rights he can then extend the node.