I hope and pray that this thread does not get neg feedback....

Ok I am trying to find the area of three points;

A=(-2,5) B=(1,3) C=(-1,0)

I am following the text books examples on how to do this and so far it's working out.BUTin the text/example it talks about the "right angle is atvertex B."

MY question is (to understand this); what does the wordvertexmean?

Thank you in advance for any reply/help