A square has an area of 100 sq. yards. What is the perimeter of the square?

I found: $40 y a r \mathrm{ds}$
Considering that the area $A$ is given as:
$A = {l}^{2}$ where $l$ is the side; you have:
$100 = {l}^{2}$ then
$l = \sqrt{100} = 10 y a r \mathrm{ds}$
The perimeter $P$ will be $P = 4 l = 40 y a r \mathrm{ds}$