how many rectangles in chessboard??explain

• we have two chose two horizontal & two vertical lines from 9 line (8*8 square sheet) to form a rectangle,square is also a rectangle
  so no. of rectangle=9c2*9c2=1296
• 10 years agoHelpfull: Yes(6) No(2)
• use formula
  no. of rectangles=[n(n+1)/2]^2
  where n=8.
  so ans=1296.
• 10 years agoHelpfull: Yes(4) No(0)
• For this we have to calculate
  no. of squares of size 1*1(position)=8*8(dimension)=1
  no. of squares of size 1*2(position)=7*7(dimension)=2
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  no. of squares of size 1*8(position)=1*1(dimension)=8
  similarly we need to calculate 2,3,4,5,6,7,and positions also
  finally we get the answer 1296
  
  short cut is (no of verticies)*(no of end points)/no of diagnols represented in each rectangle)
  so the answer is (9*9)*(8*8)/4=1296. |
  
• 10 years agoHelpfull: Yes(3) No(0)
• answer is 1296
  number of rectangles is estimated by n^3 formula where n is 8 here.
• 10 years agoHelpfull: Yes(1) No(3)