Thank you. Can you explain how did you get 25x12 and 48x12?

Triangle:
1,2,3,4,5,6,7,8,9,10...........22,23,24,25
We pair the number:
1+24 =25
2+23 =25
3+22 =25
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12+13 = 25
Total have 12 pair of 25,
so 12 x 25 plus the last 25 without pair...

same for Square
1,3,5,7,9,11.... 45,47,49
pair the number:
1+47 =48
3+45 = 48
5+43 = 48
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12 pair of 48
12 x 48 plus the last number 49
..
....
........

Thank you so much for the detailed explanation!