The length, breadth and thickness of a rectangular sheet of metal

Question.

The length, breadth and thickness of a rectangular sheet of metal are $4.234 \mathrm{~m}, 1.005 \mathrm{~m}$, and $2.01 \mathrm{~cm}$ respectively. Give the area and volume of the sheet to correct significant figures.

solution:

Length of sheet, $I=4.234 \mathrm{~m}$

Breadth of sheet, $b=1.005 \mathrm{~m}$

Thickness of sheet, $h=2.01 \mathrm{~cm}=0.0201 \mathrm{~m}$

The given table lists the respective significant figures:

The length, breadth and thickness of a rectangular sheet of metal are 4.234 m, 1.005 m, and 2.01 cm respectively. Give the area and volume of the sheet to correct significant figures.

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

Surface area of the sheet $=2(l \times b+b \times h+h \times l)$

$=2(4.234 \times 1.005+1.005 \times 0.0201+0.0201 \times 4.234)$

$=2(4.25517+0.0202005+0.0851034)$

$=2 \times 4.36$

$=8.72 \mathrm{~m}^{2}$

Volume of the sheet = l × b × h

$=0.0855 \mathrm{~m}^{3}$

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

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