Question

the length breadth and thickness of a rectangular sheet is 4.234 m , 1.005 m and 2.01cm respectively . give the area and volume of the sheet correct to significant figures

Answer 1

Length of sheet, l = 4.234 m

Breadth of sheet, b = 1.005 m

Thickness of sheet, h = 2.01 cm = 0.0201 m

The given table lists the respective significant figures:

Quantity	Number	Significant Figure
l	4.234	4
b	1.005	4
h	2.01	3

Hence, area and volume both must have least significant figures i.e., 3.

Surface area of the sheet = 2 (l × b + b × h + h × l)

= 2(4.234 × 1.005 + 1.005 × 0.0201 + 0.0201 × 4.234)

= 2 (4.25517 + 0.02620 + 0.08510)

= 2 × 4.360

= 8.72 m²

Volume of the sheet = l × b × h

= 4.234 × 1.005 × 0.0201

= 0.0855 m³

This number has only 3 significant figures i.e., 8, 5, and 5.