This is the horizontal vector in the diagram above. He ran backwards 5 meters per second.
This is the vector labeled "throw" above. Remember, you can find the rectangular components using:[br][math]throw=\ll vcos\theta,vsin\theta\gg[/math]
You need to combine his backward run vector with his throwing vector to get the components of the resultant vector.
Find the magnitude of the resultant vector...
You know the two legs of a right triangle, need to find the angle that is made with the horizontal leg.