Question
The length, breadth and height of a cuboid are $4.234 m, 1.005 m$ and 2.01 cm . Find its area and volume to correct significant figures.
✓
Answer
$\begin{aligned}
L & =4.234 m \\
B & =1.005 m \\
H & =2.01 cm=0.0201 m \\
\text { Area } & =? \\
\text { Volume } & =?
\end{aligned}$
Area and volume to be found to correct significant figures.
$\begin{aligned}
\text { Area of cuboid } & =2(L \times B+B \times H+H \times L) \\
& =2(4.234 \times 1.005+1.005 \times \\
& 0.0201+0.0201 \times 4.234)
\end{aligned}$
$\begin{array}{l}
=2(4.255+0.0202+0.0851) \\
=2 \times 4.360=8.720
\end{array}$
Rounded to three significant figures since the least significant figure in height is three $=8.72 m^2$
$\begin{aligned}
\text { Volume of cuboid } & =L \times B \times H \\
& =4.234 \times 1.005 \times 0.0201 \\
& =0.0855
\end{aligned}$
Rounded off to $0.086 m^3$
L & =4.234 m \\
B & =1.005 m \\
H & =2.01 cm=0.0201 m \\
\text { Area } & =? \\
\text { Volume } & =?
\end{aligned}$
Area and volume to be found to correct significant figures.
$\begin{aligned}
\text { Area of cuboid } & =2(L \times B+B \times H+H \times L) \\
& =2(4.234 \times 1.005+1.005 \times \\
& 0.0201+0.0201 \times 4.234)
\end{aligned}$
$\begin{array}{l}
=2(4.255+0.0202+0.0851) \\
=2 \times 4.360=8.720
\end{array}$
Rounded to three significant figures since the least significant figure in height is three $=8.72 m^2$
$\begin{aligned}
\text { Volume of cuboid } & =L \times B \times H \\
& =4.234 \times 1.005 \times 0.0201 \\
& =0.0855
\end{aligned}$
Rounded off to $0.086 m^3$
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