Find X

As the triangles are similar, we can relate the lengths by ratios...:

$\dfrac{1\frac{5}{6}}{2\frac{1}{4}} = \dfrac{x}{1\frac{1}{2}}\\ x = 1\dfrac{5}{6} \times 1\dfrac{1}{2} \div 2\dfrac{1}{4} = 1\dfrac{2}{9}$