A square is very much a rectangle – the definition of a rectangle is simply “all angles are right angles” which is certainly satisfied by a square. We should subtract only if specifically asked to do so. In a similar manner, a rectangle is a parallellogram (and so is a rhombus)
CAT-holics 
We should subtract number of squares from 1296 or we are taking advantage of the fact that square is a special type of rectangle?
A square is very much a rectangle – the definition of a rectangle is simply “all angles are right angles” which is certainly satisfied by a square. We should subtract only if specifically asked to do so. In a similar manner, a rectangle is a parallellogram (and so is a rhombus)
regards
J
Hello J,
In case of the rectangle why are we taking 9C2 ? Could you please explain as i am unable to get 😦
Choosing any 2 out of the 9 horizontal lines which demarcate the rows, and any 2 out of the 9 vertical lines which demarcate the columns.
regards
J
Thanks J