2006 Cayley Problem 18

In a right-angled triangle, the sum of the squares of the three side lengths is 1800. The length of its hypotenuse is

\textbf{(A)}\ \sqrt{1800}\quad \textbf{(B)}\ \frac{1}{2}\sqrt{1800}\quad \textbf{(C)}\ 90\quad \textbf{(D)}\ 30\quad \textbf{(E)}\ 45

If there are no answer choices shown, enter a numerical answer.

Full credit to this problem is given to the CEMC, you may view all Cayley contests here.