title: How to calculate the angle between three points based on Latitude/Longitude
body: <p>Below is the map that captures from Google Map. I want to calculate the angle ABC. I have the coordinate (Latitude/Longitude) of three points.</p>
  
  <p>Is there any approach to resolve my problem?</p>
  
  <p>Thanks</p>
  
  <p><img src="https://i.stack.imgur.com/G7wip.png" alt="enter image description here"></p>