By setting them in ratio do you mean,
atan[{√(d(y)/- 4.905) }/{d(x)/10}] = 20°
tan 20° = .3640
.364(d(x)/10) = √(d(y)/- 4.905)
Which means I am still left with two variables and one equation, or, do you mean.
dx : dy = cos(20°) : sin(20°)
dy = 2.747 dx
dx = 0.364 dy
which...