Lab Manual: Mid-point and Perpendicular Bisector of a Line Segment | Lab Manuals for Class 9 PDF Download

Objective

Prerequisite Knowledge
Definition of mid-point and perpendicular bisector.

Definition of Mid-point: A point which divides the line segment into two equal parts is known as a mid-point of a line segment. M is the mid-point of AB.

Concept of perpendicular bisector: A line which is perpendicular to the given line segment and divides it into two equal parts is known as perpendicular bisector of the given line segment.

Materials Required
Tracing papers, geometry box, a pair of scissors.

Procedure

• Take a square sheet of tracing paper and draw a line segment PQ of desired length as shown in fig. (i).

fig. (i)

• Fold this sheet along the middle in such a way that point P falls on point Q fig.(ii).

• Press the paper properly, so that a crease is obtained. Unfold the paper and draw the dotted line over the crease.
  Name it AB as shown. Name the point of intersection of line AB and PQ as M fig. (iii).
  

Observation
This point M is mid-point of line segment PQ and the crease obtained is perpendicular bisector of PQ.

Objective

Materials Required
Tracing papers, geometry box, a pair of scissors.

Procedure

• Take a piece of tracing paper and draw a line segment PQ of desired length as shown in fig.(i).

fig. (i)

• Take any point M on the line segment PQ, now fold the paper in such a way that PM falls on MQ as shown in fig.(ii) and fig.(iii). Press the paper

Fig. (ii)

• Open the paper, a crease is formed at M. Draw a dotted line on this crease with pencil and name it as ML.

Fig. (iv)

In the same way a perpendicular can be drawn from the point outside the line segment. Hence point M lies outside the line segment PQ.

• On tracing paper, draw figure (v) (a) as shown. Fold the paper along line PQ in such a way that its two opposite corners come close together as shown in (b). Press it and mark the image of point M. Name it M’, unfold the paper.
• Join M and M’. MM’ is perpendicular to PQ.
  

Result
In this way, we find mid-point of line segment and perpendicular bisector of line segment.

Learning Outcome
By paper folding activity, students will be able to find the mid-point, perpendicular bisector of any line segment and draw perpendicular from any point lying on or outside the line segment.

Activity Time

• Take any triangle and draw perpendiculars from the opposite vertex to corresponding side of a triangle.
• Take any triangle and find the mid-points of three sides by paper folding activity.
• Take any quadrilateral and find the mid-points of four sides by paper folding activity.