I was in an accident in a parking lot at school. Before I started to back out I looked over my shoulder to see if any cars were coming from either direction. I saw the car go past me so I looked again to see if any cars were coming. I proceeded to back out of the spot, I then looked towards the passenger side and saw the same car that just passed me coming in revers towards me. I honked my horn and started yelling for the car to stop but he continued coming towards me and hit my rear passenger side causing some pretty decent damage. Who is at fault?

Did the police come to the scene? Typically they will determine who is at fault in their accident report.

Usually in a situation like a parking lot it is equal fault.