Alright so I thought I understood this well. I'll give an example of how I solve for range and such with the given information: A ball is thrown from a height of 1.86 m, at a speed of 21 m/s and at an angle of elevation of 59.4o. How far from the person who threw it does the ball land? Range: Vxt Vx: Vcos Theta Vy: V sin Theta The method in which I solve for t goes as follows: Vy = 21 * sin59.4 Vy = 18.07 Maximum Height: v²= 2a(s) +existing height of 1.86 Maximum height: 18.07² /2(9.8) = s -> 16.66 + 1.86 = 18.52m Total time: Time down + Time Up s + 1.86 = 1/2at² + s = 1/2at² 18.52*2 / 9.8 = t² + 16.66 * 2/9.8 = t² 1.94 + 1.84 = 3.78s R = V cos Theta * t R = ~40.4 m The problem I encounter is simply that I do not know how, using this method, or by any other really, to compute the angle or initial velocity if Total time is not a given already. Say the equation was rearranged and said: A person threw the ball at an initial rate of 21 m/s from a height 1.86. It hit the ground at 40.4m. What was the angle of projection? Can anyone help show me how to work these backwards? Would be highly appreciated.