If there are 9 horizontal lines and 9 vertical lines in a chess board, how many rectangles can be formed in the chess board? Answers:
A) 1136
B) 1268
C) 1244
D) 1296
E) 1308
Here m = 9, n = 9   Hence, number of rectangles that can be formed   = mC2 × nC2   = 9C2 × 9C2 = (9C2)^2   = 36^2   =1296   Ans-1296
<result>D</result>
If there are 9 horizontal lines and 9 vertical lines in a chess board, how many rectangles can be formed in the chess board?