From the question, it’s given that
Length of the room = 8 m 25 cm = 825 cm
Breadth of the room = 6 m 75 cm = 675 cm
Height of the room = 4 m 50 cm = 450 cm
The required longest rod which can measure the room exactly is the HCF of 825, 675 and 450.
First, consider 675 and 450 and apply Euclid’s division lemma,
675 = 450 x 1 + 225
450 = 225 x 2 + 0
Therefore, the HCF (675, 450) = 225
Now, consider 225 and the third dimension i.e., 825
By applying Euclid’s division lemma to the above,
825 = 225 x 3 + 150
225 = 150 x 1+75
150 = 75 x 2 + 0 (here the remainder becomes 0)
Thus, HCF (225, 825) = 75.
Therefore, HCF of 825, 675 and 450 is 75.
And, the length of the longest rod is 75 cm or 0.75 m.