Everybody's hall is different so you have to measure your hall
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The question is about one "half", not one "hall".
Unfortunately, the questioner does not say one and one half what (inch, foot, mile, micron, nanometre, etc) so it is impossible to give a sensible answer.
There are exactly 1.5 inches in one and one half inches.
1.5 inches.
6 inches in one half foot.
0.5 inches.
1.5 inches
six and one half
42 inches
Eighteen inches.
One yard and a half = 1.5 x 36 inches = 54 inches.
It is 54 inches.
There are two half-inches in one inch.
It should be 95040 inches