Question

Find the longest pole (to nearest metres) that can be placed in a room $3m\times 4m\times 12m$.

• A. $8m$
• B. $13m$
• C. $9m$
• D. $15m$

Answer 1

The correct option is B $13m$

Length of longest pole that can be placed in a room $=$ Length of diagonal

$=\sqrt{l^2+b^2+h^2}$[where $l=3m,b=4m,h=12m$]

$=\sqrt{3^2+4^2+{12}^2}$

$=\sqrt{9+16+144}$

$=\sqrt{169}$

$=13$

So, Required length of pole $=13m$

Hence, $\text{B}$ is the correct option.