Page 189 - Maths Skills - 8

Mensuration 187

Activity

Objective: To derive the formula of surface area of a cuboid and a cube.

Previous Knowledge Required: Cuboid and area of a rectangle.

Materials Required: Cardboard, a pair of scissors, an adhesive tape, geometry box. You can use an empty pack
of tea leaves etc. for a cuboid.

Procedure: 1. Take length, breadth and height of your choice to make a cuboid as shown in Fig. 1.
2. Cut the cuboid into 6 different rectangles.
3. Fix the rectangular pieces with an adhesive tape to make a net as illustrated in Fig. 2.
4. Measure the area of each rectangle and record your observations in the table.

Back

Bottom

Front

Fig. 1 Fig. 2

Observations:
Area of Rectangle 1 2 3 4 5 6
(l × b) (l × b) (b × h) (b × h) (h × l ) (h × l )

In Sq. cm.