Question

How many acres are there in the W 1/2 of the S 1/2 of the SW 1/2 of a section of land? 50 acres? 15 acres? 80 acres? 160 acres?

Answer 1

1/2 of 1/2 of 1/2 = 1/8.

There are 640 acres in a section, so 1/8 section = 80 acres.

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In surveying terms, "SW 1/2 of a section" is not a realistic specification of a piece of property.