This is the problem: Let's ignore the second part, because I can't even get to there yet (sounds simple enough if I figured out the first part). What I am stuck on, is the fact I have no initial velocity or time. So I have two unknowns. Here is what I think I know. The acceleration is 9.8 m/s^2 due to gravity. Since I have the same y position, at the highest point P, where the velocity is 0, it should be exactly in the middle? So 100m. If I use, 100m as x when y is at it's highest, I can turn that into a right angle. And do: (100)*tan 45 degrees = 100m. So the height at point P is 100m. I'm assuming these are the only equations I am suppose to use: v= v(i) + at x = x(i) + v(i)t + 1/2at^2 v^2 = v(i)^2 + 2a(x-x(i)) x=100m y=100m t=? v(i)=? a=9.8 m/s^2 and also for y, since they are independent. And I think x and y have the same answer in this case, because they both have the same magnitude (at least cut in half). However, it doesn't look like I can solve for anything in any of the equations. What should I be doing next?