Originally Posted by
QuiltnNan
9" finished blocks with 9 rows across and 10 rows down
straight set is 83x92"
on point is 116x130"
But this change in measurement involves having additional fabric for the setting triangles and extra blank 9" sqares of fabric as Dunster points out in her diagram. A straight set doesn't have those, so you need to keep that in mind patchitpat.
As Bear pointed out a 9 x 9 block only has a finite number of square inches of surface area no matter how you set it. The increased size is because of the additional fabric used in the setting triangles and alternate squares.