Answer:
They are saying that they have this conference room mapped out on a poster board kinda like a road map. But if you put something that big on a board it wont fit. So they had to make it small enough to fit it. When they say that 1/2 on the board is equal to 12 feet in the real room, They are tell you the scale you have to go by. So then they give you 3 1/2 inches on the board. You would see how many 1/2 inches there are in 3 1/2, which is 7, and multiply 7 by 12. The answer would be 84 feet. So they are say that 3 1/2 inches on the poster board, represents 84 feet in the real room.
Explanation: