Page 86 - Mathematics Class - XII

ACTIVITY 7.2

OBJECTIVE

To measure the shortest distance between two skew lines and verify it analytically.

MATERIAL REQUIRED
Y A piece of plywood / cardboard of size 30 cm × 20 cm

Y Three wooden blocks of size 2 cm × 2 cm × 2 cm each
Y One wooden block of size 2 cm × 2 cm × 4 cm
Y Wires of different lengths

Y A graph paper
Y Set squares

Y Adhesive
Y Pen/pencil

PRE-REQUISITE KNOWLEDGE
1. Knowledge of the concept of skew lines, coplanar lines.
2. Knowledge of the concept of shortest distance between two lines.

PROCEDURE

1. Take a plywood or cardboard of convenient size and paste a graph paper on it.
2. On the graph paper, draw two lines OX and OY to represent x-axis and y-axis, respectively.
3. Label the three blocks of size 2 × 2 × 2 cm
as I, II and III. Label the other wooden
block of size 2 cm × 2 cm × 4 cm as IV.

4. Place blocks I, II, III such that their base
centres are at the points (2, 2), (1, 6) and
(7, 6), respectively, and block IV with its
base centre at (6, 2).

5. Place a wire joining the points P and Q, the
centres of the bases of the blocks I and III
and another wire joining the centres R and
S of the tops of blocks II and IV as shown
in Fig. (a).
6. These two wires represent two skew lines.

7. Take a wire and join it perpendicularly
with the skew lines and measure the actual
distance. Fig. (a)

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