Thread: chessboard problem

in a chessboard how many rectangles are there whose area is equal to 3 times the area of a small square

Originally Posted by prasum

in a chessboard how many rectangles are there whose area is equal to 3 times the area of a small square

The rectangles require 3 consecutive squares in a straight line.
Each of the 8 rows contains 6 sets of 3 horizontally adjacent squares.
That's 6 rectangles per row over 8 rows.
The rectangles in the columns can be counted in the same way.
There are no diagonal rectangles.

Originally Posted by Archie Meade

The rectangles require 3 consecutive squares in a straight line.
Each of the 8 rows contains 6 sets of 3 horizontally adjacent squares.
That's 6 rectangles per row over 8 rows.
The rectangles in the columns can be counted in the same way.
There are no diagonal rectangles.

thanks