Given that Juan's house has a rectangular doorway that is 8 feet high and 3 feet wide.
We have to find the diagonal of doorway.
It is known that the length of the diagonal of rectangle is:
![d=\sqrt[]{l^2+w^2}](https://img.qammunity.org/2023/formulas/mathematics/college/h71o55h43rrf4ifsrkkogpz9lauv3g4g4b.png)
Substitute l = 8 and w = 3.
![\begin{gathered} d=\sqrt[]{8^2+3^2} \\ =\sqrt[]{64+9} \\ =\sqrt[]{73} \\ =8.544 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/h512cnt5mr9ugrpfiiumukt89wzmftpfur.png)
Thus, the second option is correct.