This presentation discusses how to draw parallel and perpendicular lines using a set square. It provides step-by-step instructions for using a set square to draw a line parallel to an existing line passing through a given point, as well as to draw a line perpendicular to an existing line passing through a point. The presentation is intended to teach proper technique for using a set square to draw parallel and perpendicular lines.

1. This presentation has been made for you by
FRANCISCO GUIJARRO BELDA
From Isaac Albéniz Secondary School
Leganés. Madrid. Spain.

2. PARALLEL LINES
1) Imagine you have a line, labeled m in the picture, and you want to draw a line
parallel to it passing through the point A. Take the set square with your hands. The
right is always for the small one and the left for the big.

3. PARALLEL LINES
2) Align the set square with line m as you see in the picture.

4. PARALLEL LINES
3) Following the arrow, move the set square in order to keep both rulers together.
Hold the big set square steadily because you are about to start.

5. PARALLEL LINES
4) gently slide the small set square along the long side of the big one (watch the
arrow on the picture).

6. PARALLEL LINES
5) Sometimes, we might also need to slide the big set square because the point is
too far away. This is not a problem, just hold the small one and move the big set
square the distance you need as illustrated in the picture below. Again, watch the
arrow.

7. PARALLEL LINES
6) Again, hold the big set square and slide the small one until the point. We are
about to finish.

8. PARALLEL LINES
7) Holding both set squares steadily with your left hand, draw the line.

9. PARALLEL LINES
8) This will be your final result.

10. PERPENDICULAR LINES
1) Do steps 1 to 3 the same manner you did for parallel lines. Then, hold the big set
square with your left hand and rotate the small one 90 degrees as you can see on
the screen.
90º

11. PERPENDICULAR LINES
2) Put this time the small set square so that it can lean on the longest side of the
big one.

12. PERPENDICULAR LINES
3) Move the small ruler just to make it go until point A (on the picture, following the
black arrow).

13. PERPENDICULAR LINES
4) Draw the line and you are done.