Parallel and Perpendicular Lines - Construction
Drawing a parallel line
- Select the POINT tool (Window 2) and draw a point B on line r.
- Select the COMPASS tool (Window 6). Then click on B and A (it represents the length opening of
the compass) and again on B (represent the sharp end of the compass).
-Select the INTERSECT tool (Window 3) and mark points C and D, which are intersection points between the circle with the line r.
- Select the COMPASS tool (Window 6). Then click on point C and point A (it represents the length opening of the compass) and again on point D (it represents the sharp end of the compass).
-Select the INTERSECT tool (Window 3) and mark point E, which is the point of intersection of the two circles. -Select the LINE tool (Window 4) and click on A and E. Label this line s.
- Select the SHOW/HIDE OBJECT tool (Window 7) and hide the circles, points C, D and E, leaving only
the lines and point A.
-Select the RELATION (Window 8) and click on the two lines. What happens when you follow all the steps above?
- Select the MOVE tool (Window 1). Move either point A or line r. What can you see?
Parallel Line
Describe how you can claim two lines are parallel.
Perpendicular line (point not belonging to line)
- Select the COMPASS tool (Window 6). Then click on the segment AB (it represents the length opening of the compass) and on E (represents the sharp end of the compass).
- Select the INTERSECT tool (Window 3) and mark F and G. They are points of intersection of the circle with the line.
- Select the COMPASS tool (Window 6). Then click on point F and point G (it represents the length opening of the compass) and again on point F (it represents the sharp end of the compass). After that, click on point G and point F (it represents the length opening of the compass) and again on G (it represents the sharp end of the compass).
- Select the INTERSECT tool (Window 3) and mark a point H, point of intersection of the last two circles.
-Select the LINE tool (Window 4) and click on point E and point H. The intended perpendicular line will appear. Let us analyse it.
- Select the INTERSECT tool (Window 3) and mark point I, point of intersection of points h and g.
- Select the ANGLE tool (Window 9). Click on points E, I and C to mark the angle EIC (the vertex of the angle will always be the second point clicked). What is the measurement of this angle?
- Select the SHOW / HIDE OBJECT tool (Window 7) and hide the circles, points H, F and G, leaving only the lines and point E.
-Select the RELATION tool (Window 8) and click on the two lines. What happens when you follow all the steps above?
- Select the MOVE tool (Window 1). Move either point E or line g. What can you see?
Perpendicular line (point not belonging to the line)
What was the measure of Angle EIC ?