Answer:
121
Step-by-step explanation:
1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 + 21 is a sum of first 11 odd numbers.
[tex]\sf \boxed{\text{\bf Sum of first n odd numbers = $n^2$}}[/tex]
Here, n is the number of terms.
In this sequence, there are 11 terms.
Sum of first 11 odd numbers = 11²
= 11 *11
= 121
