The first thing you need to know is that the slope of a perpendicular line is the opposite reciprocal of the other slope. Find the slope of this line, which is -2. The opposite reciprocal is 1/2. So, you know that the perpendicular line is equal to y=1/2x. Plug the x coordinate (4) in for x to have: y=1/2(4). Multiply 4 by 1/2 to get y=2. Since the y coordinate is supposed to equal 5, add 3 to y=2 to get 5. Since 3 is the amount we added, thats where the y intercept will be. Hope this helped!
