25
4 rectangles
depends on what size triangles and what kind of triangles?
36
90
There are 2025 rectangles in a 9x9 grid.
25
That depends on how big the rectangles are.
96 rectangles.
4 rectangles
441
Oh, dude, let me count... Okay, so in a 5 by 6 grid, you've got like 15 horizontal rectangles and 10 vertical rectangles, but don't forget the big one that covers the whole grid, so that's like 26 rectangles total. So, like, yeah, there you go.
62 x 38 = 2356 rectangles
depends on what size triangles and what kind of triangles?
36
90
14