I am including a diagram. I hope I am interpreting correctly.
We can use the horizontal and vertical component formulas.
When the rock is level with the point it was thrown, then it's the point where y equals 0, we can find x at that time.
Solving for t we find t=2.04 seconds to reach that point.
That means it's x coordinate is
The stone is at (35.35,0) at 2.04 seconds.
Now, we have a triangle with angle 45 and side 35.35
So, the y component is the same, y=-35.35 feet
Plug this into the y component and solve for t.
And we find t=3.89 seconds
Perhaps TopsQuark will check me out.