Hello,cesar2012!
I know the coordinates of points E and Q, so I know their euclidean distance L.
I'm looking for the point W with coordinates (a,b) related to other known values.
Code:* * * W o-----o R * * * | * * * | * r* @| * *| * * o Q * * * | * * | * * | * L * | * * * | * * * * * * | * @ | E o-----------------o P
Note that: .$\displaystyle \angle W\!QR \,=\,\angle QEP \,=\,\theta$
In $\displaystyle \Delta QPE\!:\;\begin{Bmatrix}EP &=& L\cos\theta \\ QP &=& L\sin\theta \end{Bmatrix}$
In $\displaystyle \Delta W\!RQ\!:\;\begin{Bmatrix}W\!R &=& r\sin\theta \\ RQ &=& r\cos\theta \end{Bmatrix}$
The x-coordinate of point $\displaystyle W$ is: .$\displaystyle x \;=\;EP - W\!R \;=\;L\cos\theta - r\sin\theta$
The y-coordinate of point $\displaystyle W$ is: .$\displaystyle y \;=\;QP + RQ \;=\;L\sin\theta + r\cos\theta$