96 rectangles.
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.
62 x 38 = 2356 rectangles
8
seven
you can make 76 different triangles on a 3x3 grid
There are 2025 rectangles in a 9x9 grid.
That depends on how big the rectangles are.
There are 36 unique quadrilaterals in a 3x3 square grid: 14 squares = 9 (1x1) 4 (2x2) 1 (3x3) 22 rectangles = 6 (1x2) 6 (2x1) 6 (3x3) 2 (2x3) 2 (3x2) (the total number of quadrilaterals formed by 3 x 3 pin sets will be larger, i.e. 78)
96 rectangles.
There are 9 boxes in a 3x3 grid.
36
4 rectangles
441
225
315
62 x 38 = 2356 rectangles