1. The problem statement, all variables and given/known data A projectile was fired across level ground at an initial angle of 43.00 degrees above the horizontal. During its flight, it reached a maximum height of 2974 metres. What was the initial speed of this projectile? 2. Relevant equations I assume that the correct equation to use is Vy2 = V0y² - 2g(y - y0). 3. The attempt at a solution To be honest I'm not even sure how to go about it. Given the equation, I would rearrange for V0y² however that doesn't seem to work at all. I'm not even sure what the value of Vy has to be. I also suspect the angle comes into play, but I'm not sure what it can tell me. Any pointers greatly appreciated.