Hi Jamie,

Google can helps with this. If you type 1 acre in square feet into the Google search window you get the reply that 1 acre is 43560 square feet. If your acre is actually a square as you say it is and the side length is $s$ feet then

\[s \times s = s^2 = 43560 \mbox{ square feet }\]

and thus

\[s = \sqrt{43560} = 208.7 \mbox{ feet }\]

or almost 209 feet as you said.

If the area of the square is 1.4 acres that's $1.4 \times 43560$ square feet. If the side length of this square is $t$ feet then

\[t^2 = 1.4 \times 43560 \mbox{ square feet.}\]

Solve for $t.$

Write back if you need more assistance,
Penny