The number of rectangles which we can form on a chess board is

Question

The number of rectangles which we can form on a chess board is (A) 81 (B) 1296 (C) 648 (D) 324

Tardigrade Admin · Accepted Answer

There ate 9 horizontal and 9 vertical lines on a chess board. To from a rectangle we require two horizontal and two vertical lines. Thus the no. of rectangles on the chess board

=^{9} C_{2} \times^{9} C_{2} = 36 \times 36

= 1296

.

Q. The number of rectangles which we can form on a chess board is

$81$

$1296$

$648$

$324$

There ate 9 horizontal and 9 vertical lines on a chess board. To from a rectangle we require two horizontal and two vertical lines. Thus the no. of rectangles on the chess board
$=^{9} C_{2} \times^{9} C_{2} = 36 \times 36$
$= 1296$ .