None, since there can be no conversion.
A linear (or lineal) foot is a measure of length in 1-dimensional space. An acre is a measure of area in 2-dimensional space. The two measure different things and, according to basic principles of dimensional analysis, any attempt at conversion from one to the other is fundamentally flawed.
834.84 feet
An acre is 43,560 square feet.An acre is 43,560 square feet.
The actual dimensions of the acre can vary greatly as long as the total area is correct. It just has to contain 43560 square feet.
An acre is defined as any area that is 43,560 square feet, and therefore doesn't have any set dimensions as it can be in the shape of a square, rectangle, triangle, etc. However, the dimensions of an acre that is a perfect square is about 208. 71 feet by 208. 71 feet.
An acre was NOT defined as 43560 feet, but as 43560 SQUARE feet. This is immediately apparent when you consider that an acre is a measure of area, with dimensions [L2]. A foot is a measure of distance, with dimensions [L]. Basic dimensional analysis teaches that you cannot convert between measures with different dimensions without additional information. An acre is equivalent to the area of 1 furlong (660 feet) by 1 chain (66 feet).
20 by 20?
An acre contains 43,560 square feet. Any combination of numbers that give you that area can be the dimensions. A square 209 feet by 209 feet is pretty close to an acre.
This question cannot be answered sensibly. An acre is a measure of area, with dimensions [L2]. A foot is a measure of distance, with dimensions [L]. Basic dimensional analysis teaches that you cannot convert between measures with different dimensions such as these without additional information.
A half acre is 21,780 square feet, it can be any combination of dimensions that equal this total.
0.125 of an acre is 5445 square feet. A square area containing that number of sq. feet would be 73.79 feet long and 73.79 feet wide.
An acre is 43,560 square feet. You'll have to do some math to decide what proportions you want that one acre lot to take.
Lineal feet are units for measuring lengths.