[tex]\begin{gathered} \text{the angle is the same in both cases} \\ \text{For the 12 f}eet\text{ tall} \\ \tan (\theta)=\frac{tall}{shadow}=\frac{12}{10}=1.2 \\ \text{For the 18 fe}et\text{ tall} \\ \tan (\theta)=\frac{tall}{shadow} \\ \text{shadow}=\frac{tall}{\tan (\theta)} \\ \text{shadow}=\frac{18}{1.2} \\ \text{shadow}=15 \\ \text{the shadow for the 18 fe}et\text{ tall is 15f}eet \end{gathered}[/tex]
