This is an mensurational problem of triangles. 1. The problem statement, all variables and given/known data In triangle ABC, anngle B=90degrees and D is the mid point of AC .If AB=20 cm and Bd=14.5cm,find the area and perimeter of the triangle ABC. My book says that BD=AD=DC=> AC=2BD=29 and so on But i can't get how could they just write that BD=AD?? I am really at my wits end. If we take this into consideration it is really easy but how do I do it when I iam not clear at the base. I tried to prove the angles equal to prove the sides but it's not working. Please help!