1950 AHSME Problem 35

In triangle ABC, AC=24 inches, BC=10 inches, AB=26 inches. The radius of the inscribed circle is:

\textbf{(A)}\ 26\text{ in}\qquad\textbf{(B)}\ 4\text{ in}\qquad\textbf{(C)}\ 13\text{ in}\qquad\textbf{(D)}\ 8\text{ in}\qquad\textbf{(E)}\ \text{None of these}

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.