Answer
$$2870$$
Work Step by Step
Given $$\sum_{k=1}^{20}(k^2)$$
Since
$$\sum_{k=1}^{n}k^2=\frac{n(n+1)(2n+1)}{6} $$
Then
\begin{align*}
\sum_{k=1}^{20}(k^2)&=\frac{(20)(21)(41)}{6} \\
&= 2870
\end{align*}
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.