Draw any line segment PQ. Take any point R not lying on it. Through R, draw a perpendicular to . (use ruler and set square)

Steps of Construction-

1. Draw a line segment PQ. Mark a point R not lying on it.

2. Place a set square on PQ such that one arm of its right angle aligns along PQ.

3. Place a ruler along the edge opposite to the right angle of the set-square.

4. Hold the ruler fixed. Slide the set square along the ruler till the point R touches the other arm of the set square.

5. Join RM along the edge through R meeting PQ at M. Then RM is perpendicular to PQ.