Page 85 - Mathematics Class - XI

TOPIC - 11: Introduction to 3-Dimensional Geometry

ACTIVITY 11.1

OBJECTIVE
To explain the concept of octants by three mutually perpendicular planes in space.

MATERIAL REQUIRED
 A piece of plywood  Rulers  Scissors
or cardboard  Wooden-board  Cutter
 Saw  Coloured chart papers  Thin sheet of wood
 Wires

PRE-REQUISITE KNOWLEDGE
1. Knowledge of concept of three dimensional geometry
2. Knowledge of representation of position of a point in space

PROCEDURE
1. Cut out three square sheets each of size 40 cm × 40 cm from a piece of plywood or cardboard and paste
different colour chart papers on both sides of each sheet.
2. Fix two sheets in such a way that they intersect orthogonally in the middle of each other (Fig. (a)).
3. Cut the third sheet into two equal rectangles.

4. Insert one rectangle from one side in the middle cutting the two orthogonally, and the other rectangle from
the other side (Fig. (a)). The space is divided into eight parts by these three sheets. Each part is referred
to as an octant.
5. Fix this model on a wooden board.

6. In one of the octants, fix rulers to represent x-axis, y-axis and z-axis. As in Fig. (b) extend each of the axis
piercing to other sides to represent XOX′, YOY′ and ZOZ′. Mark the point of intersection of XOX′, YOY′
and ZOZ′ as origin O.

Fig. (a) Fig. (b)

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