Question

Qs.1. a rectangular wooden crate has inside 3 dimensions, 3 meters by 4 meters by 12 meters. what is the length in meters, of the longest, straight, inflexible rod of negligible diameter that can be placed completely within the crate

Answer 1

$\sqrt{x {}^{2} + y {}^{2} + z {}^{2} }$
x = length
y =breadth
z =height
so answer-
$\sqrt{3 {}^{2} + 4 {}^{2} + 12 {}^{2} } \\ = 13 metres$