Question

Take a point R on line XY. Draw a line perpendicular to XY at R, using a set square.

Answer 1

Steps of constructions:
1. Draw line XY. Take point R anywhere on the line.
2. Place the set square on the line in such a way that the vertex of its right angle is at point R and one arm of the right angle falls on line XY.
3. Draw a line PQ along the other arm of the right angle of the set square.
4. The line RS is perpendicular to the line XY at R.