The length, bread

To find the length of the longest rod that can measure the dimensions of the room exactly, we have to find HCF.

Length, L = 8 m cm = 850 cm = 21 × 52 × 17

Breadth, B = 6 m 25 cm = 625 cm = 5⁴,

Height, H = 4 m 75 cm = 475 cm 5² × 19

⇒ HCF of L, Band H is 5² = 25 cm.

⇒ Length of the longest rod = 25 cm