Question

The length, breadth and thickness of arectangular sheet of metal are 4.234 m, 1.005 m, and 2.01 cmrespectively. Give the area and volume of the sheet to correctsignificant figures.

Answer 1

Length ofsheet, l = 4.234 m

Breadth ofsheet, b = 1.005 m

Thicknessof sheet, h = 2.01 cm = 0.0201 m

The giventable 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.

Surfacearea 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 ofthe sheet = l × b × h

= 4.234 × 1.005 × 0.0201

= 0.0855 m³

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