In a right triangle with a 45-degree angle, the two legs are equal in length, and they are related to the hypotenuse by the formula:
\[ \text{Hypotenuse} = \text{leg length} \cdot \sqrt{2} \]
For the second triangle, where the side opposite the 45-degree angle has a length of 14, the calculation of the hypotenuse will be:
\[ \text{Hypotenuse} = 14 \cdot \sqrt{2} \]
So, the hypotenuse of the second triangle has length \( 14\sqrt{2} \).
Thus, the correct response is:
The hypotenuse of the second triangle has length \( 14\sqrt{2} \).