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Find the sum: 9²+ 10²+11²+.........20².​

1 Answer

6 votes

Answer:

2666

Explanation:

9² + 10² + 11² + ......... 20² =

= 9² + 10² + 11² + 12² + 13² + 14² + 15² + 16² + 17² + 18² + 19² + 20² =

= 81 +100 +121 +144 +169 +196 +225 +256 +289 +324 +361 +400 =

= 2666

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