Answer:
[tex]\huge\boxed{a=\dfrac{16}{3}=5\dfrac{1}{3}}[/tex]
Step-by-step explanation:
[tex]\triangle ZYW\sim\triangle WYX\ (AAA)\\\\\text{Therefore corresponding sides are in proportion}\\\\\dfrac{YX}{YW}=\dfrac{YW}{ZY}\\\\\text{substitute}\\\\YX=a;\ YW=4;\ ZY=3\\\\\dfrac{a}{4}=\dfrac{4}{3}\qquad\text{multiply both sides by 4}\\\\4\cdot\dfrac{a}{4}=4\cdot\dfrac{4}{3}\qquad\text{cancel 4}\\\\a=\dfrac{16}{3}[/tex]
