Question

Draw any line segment $\overline{PQ}$. Take any point R, not on it, through R, draw a perpendicular to $\overline{PQ}$. (use ruler and set-square).

Answer 1

$\left(1\right)$ Take the given line segment $\overline{PQ}$ and mark any point R outside $\overline{PQ}$.
$\left(2\right)$ Place a set square on $\overline{PQ}$ such that one arm of its right angle aligns along $\overline{PQ}$.
$\left(3\right)$ Place the ruler along the edge opposite to the right angle of the set square.
$\left(4\right)$ Hold the ruler fixed. Slide the set square along the ruler till the point R touches the other arm of the set square.
$\left(5\right)$ Draw a line along the edge of the set square which will be passing through R. It is the required line, which is perpendicular to $\overline{PQ}$.