1972 AHSME Problem 1

The lengths in inches of the three sides of each of four triangles I, II, III, and IV are as follows:

\begin{array}{rlrl} \hbox{I}& 3,\ 4,\ \hbox{and}\ 5\qquad & \hbox{III}& 7,\ 24,\ \hbox{and}\ 25\\ \hbox{II}& 4,\ 7\frac{1}{2},\ \hbox{and}\ 8\frac{1}{2}\qquad & \hbox{IV}& 3\frac{1}{2},\ 4\frac{1}{2},\ \hbox{and}\ 5\frac{1}{2}.\end{array}

Of these four given triangles, the only right triangles are

\begin{array}{l} \text{(A) I and II}\qquad \text{(B) I and III}\qquad \text{(C) I and IV} \quad \\ \text{(D) I, II, and III} \qquad \text{(E) I, II, and IV } \end{array}

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