Set up a proportion and solve for the missing term.<br><br>
&bull; _ : 20 = 9 : 12 means \(\frac{x}{20} = \frac{9}{12}\)<br>
&bull; Simplify the right ratio: 9 : 12 = 3 : 4 (divide both by 3)<br>
&bull; So \(\frac{x}{20} = \frac{3}{4}\)<br>
&bull; Cross multiply: 4x = 60, so x = 15<br><br>
Final Answer: 15