Question

Determine the number of rectangles that can be formed on a chess-board.

Answer 1

we have formula,

number of rectangles in a $8\times 8$ chessboard

$=\frac{n^2\times (n+1{)}^2}{4}$

$=\frac{8^2\times (8+1{)}^2}{4}$

$=1296$