This is a video tutorial I made to answer a question posted by Sabrina, one of the students who commented on my post

Here’s the question she asked

March 24th, 2010 at 9:32 pm editcan you help me to solve this add math question? No diagram is given for this question. PQR is a right angled triangle with its point R lying on the line y=3x. P is (5,5)and Q is (2,1). Find the two possible coordinates of R.

and here’s the video tutorial I made to solve the question.