Answer:
ED = 6
Step-by-step explanation:
Since the triangles are similar then the ratios of corresponding sides are equal, that is
[tex]\frac{ED}{BA}[/tex] = [tex]\frac{EF}{BC}[/tex] , substitute values
[tex]\frac{ED}{9}[/tex] = [tex]\frac{12}{18}[/tex] ( cross- multiply )
18 ED = 108 ( divide both sides by 18 )
ED = 6
