title: VBA Calculate angle relative to graph
body: <p>In the last week I tried to calculate angle between three points - <br/>
  first I needed to get the points = easy<br/>
  than to calculate the angle (not relatively) = easy too</p>
  
  <p>and now I need to get the angle relative to the graph - the problem is that I dont know how (I am sure this is easy too).</p>
  
  <p>PI = 3.141592654<br/>
  A(2004,227)<br/>
  B(2005,18)<br/>
  C(2006,25)</p>
  
  <p>Here's the function/formula to calculate the Angle > </p>
  
  <pre><code>arctan((Xb - Xa)/(Ya - Yb)) * (180/PI) + arctan((Xc - Xb)/(Yc - Yb))  * (180/PI)
  </code></pre>
  
  <p>What do I need to add to the formula so it will be relatively to the graph? (I want an explanation too please)</p>
  
  <p>Here's the graph:
  <img src="https://i.stack.imgur.com/0ulsL.png" alt="enter image description here"></p>
  
  <p>Thank you very much!</p>