Units are not a consistent form of measure and are used to delineate measure. (I.e. one unit of a predetermined size is exactly equivalent to another unit, but until the unit is defined in context, it has no meaning.)
Therefore your answer is indeterminate.
However, if by units you mean AU or Astronomical Units, your answer is
8 * 92,955,887.6 miles per AU = 743,647,100.8 AU
yes
Miles and square miles are units of different measurements. Miles are units of length and square miles are units of area. There is no answer to your question.
Units are not a consistent form of measure and are used to delineate measure. (I.e. one unit of a predetermined size is exactly equivalent to another unit, but until the unit is defined in context, it has no meaning.) Therefore your answer is indeterminate. However, if by units you mean AU or Astronomical Units, your answer is 8 * 92,955,887.6 miles per AU = 743,647,100.8 AU
An acre is a unit of area. A mile is a unit of distance. The two units are therefore incompatible.
The units are the same. So there are 800 miles in 800 miles.
8
The answer will depend on the units. 20 mm x 8 mm is quite a different size from 20 miles x 8 miles.
29 Astronomical Units = 2,695,718,410.7 miles.
Approximately 82,165,500,000 miles (rounded)
149,600,000 Astronomical Units = 1.39061888 × 1016 miles.
5 Astronomical Units = 464,779,036 miles.
19.18 Astronomical Units = 1,782,892,383.4 miles.