SOLUTION
All we need to do is to draw a straight-line from the point B that is perpendicular to AC and that will meet AC at D.
This is shown below
From the question you asked; based on the construction what do we know about triangle ABD and triangle BCD what is this supposed to show me?
The line BD bisects the line AC perpendicularly, hence this has made triangle ABD and triangle BCD to be right-triangles
