Can someone help me with this please? If the painting is 18 inches high, how wide would it be?

The ratio of width to height is :
[tex]\frac{w}{h}=\frac{1+\sqrt[]{5}}{2}[/tex]If h = 18 inches, the value of w will be :
[tex]\begin{gathered} \frac{w}{18}=\frac{1+\sqrt[]{5}}{2} \\ \text{Cross multiply :} \\ 2w=18(1+\sqrt[]{5}) \\ w=\frac{18(1+\sqrt[]{5})}{2} \\ w=9(1+\sqrt[]{5}) \\ w=9+9\sqrt[]{5}\quad or\quad 29.12 \end{gathered}[/tex]The answer is w = 29.12 inches