Find the length of the largest rod which can be placed in a room of dimensions 12 m, 16 m, 20 m?

17 cm  20 cm 20\(\sqrt{2 }\) cm 19\(\sqrt{2 }\) cm

20\(\sqrt{2 }\) cm

Length of largest rod = diagonal of cuboid = \(\sqrt {(l)² + (b)² + (h)² }\) = \(\sqrt {(12)² + (16)² + (20)² }\) = \(\sqrt {144 + 256 + 400}\) = \(\sqrt {800}\) = 20\(\sqrt{2 }\) cm