There is a number in the box \(\square\) such that \(\square,\;24,\;9,\;12\) are in proportion. The number in the box is ____.
There is a number in the box such that 18, 24, 9, 12 are in proportion. The number in the box is 18.
Proportion means \(\dfrac{x}{24}=\dfrac{9}{12}=\dfrac{3}{4}\Rightarrow x=24\times\dfrac{3}{4}=18\).