title: Resolve task. Extend current line and get value
body: <p>I'm looking for solve for this task. The language is C#.</p>
  
  <p>There is an X and Y coordinate system.
  The task is to extend the current line at the same angle and print the value of this line through the specified number of steps on the X scale. </p>
  
  <p>For example: what will be Y value when the X value will go to 20? 
  How can I code it? </p>
  
  <p>Image below is example of what I need to get:</p>
  
  <p><img src="https://i.stack.imgur.com/W9489.png" alt="Example"></p>
  
  <p>Also if you can, explain please the code. The problem is that line in task could be at random angle in each task. </p>