Answer
$$H=300$$
Work Step by Step
We are given the following equation:
$$ H=\frac{1}{2}(n^2-n)$$
Plugging in $25$ for $n$, we find:
$$H=\frac{1\cdot \left(25^2-25\right)}{2} \\ H=\frac{600}{2} \\ H=300$$
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.