

Given length of the hall = 10 m
Breadth of the hall = 10 m
and Height of the hall = 5 m
Now, length of the longest pole = length of the diagonal of the hall
=> length of the longest pole =√{(10)2 + (10)2 + 52 }
=> length of the longest pole =√(100 + 100 + 25)
=> length of the longest pole =√225
=> length of the longest pole = √(15*15)
=> length of the longest pole = 15 m
