 
       
      
    8. In right triangle ABC, right angled at C, M is the mid-point of hypotenuse AB. C is joined to M and produced to a point D such that . Point D is joined to point B (see Fig.). Show that: 
 is a right angle. 
    
 
                
                  In the previous part, we have proved that   .
By c.p.c.t. we can say that :  
This implies side AC is parallel to BD.
Thus we can write :      (Co-interior angles)
and, 
or 
Hence  is a right angle.
 
                