- Find the midpoint M between 0 en P.
- Find the equation of the line L going through 0 and P
- Find a vector perpendicular to the line L
- Construct the equation of the line R going through M and perpendicular through L
- Find Q as the intersection between R and the y-axis.
All of these questions involve nothing more than 10th grade geometry. So you should be able to complete these easily.