The length of the longest pole that can be kept in a room (12 m × 9 m ×8 m) is

(d) 17 m
Length of the longest pole that can be kept in a room =Length of the diagonal of the room

$=\sqrt{l^{2+} b^{2}+h^{2}} \mathrm{~m}$

$=\sqrt{(12)^{2}+(9)^{2}+(8)^{2}} \mathrm{~m}$

$=\sqrt{289} \mathrm{~m}$

$=17 \mathrm{~m}$