81
9
None they're all squares.
9 (six rectangles = three squares)
In a 4 by 4 grid, there are 16 squares (1x1 squares), 9 rectangles that are 2x1, 6 rectangles that are 3x1, 4 rectangles that are 2x2, and 1 rectangle that is 4x4. Therefore, in total, there are 16 squares and 20 rectangles in a 4 by 4 grid.
-9
9 obvious, 3 for each row, 3 for each column, 4 for each rectangle of 4 squares, all of the squares. So 19
There are 81 squares in a 9 by 9 square.
9 x 9 = 81 squares.
81 Squares -- Deo Math Club
First of all, I do not see how you can have 9*10 sq ft squares. If they are squares, then the length and the width must be the same - otherwise they are not squares!Next, the answer depends on the shape of the lot. If the lot is 8 ft * 1000 ft, then not a single 9*10 shapes will fit. Even though the lot is wide enough, it is too narrow.If you allow the squares that are actually rectangles, to be chopped up when necessary, you can fit 8000/(9*10) = 8000/90 = 88.88... of them.
Multiple them! 3x3=9 squares!