Asquare plot of land has a building 60 ft long and 50 ft wide at one corner. the rest of the land outside the building forms a parking lot. if the parking lot has area 16,600 ft2, what are the dimensions of the entire plot of land?
ft
width

-- The building sits on (60 x 50) = 3,000 square feet.

-- The parking lot, occupying the rest of the square plot, is 16,600 square feet.

-- The total real estate is (3,000 + 16,600) = 19,600 square feet.

You said that the plot is a square.  That's valuable information.  Without
knowing that factoid, we wouldn't be able to calculate the dimensions, even
knowing the area.

-- The area is (length) x (width).  The length and width of a square are
the same number, so the area is (length or width)², and the length and
width are both √(area).

     Length  =  Width  =  √(19,600 square feet)  =  140 feet .