Life size dimension divided by scale = scale dimension
32' life size at 1/32 scale = 1.000'
32' life size at 1/48 scale = 0.006'
32' life size at 1/72 scale = 0.500'
The opposite is true as well:
scale dimension times scale = life size dimension
1' scale size at 1/32 scale = 32' life size
etc.