Answer:
B
Step-by-step explanation:
Given that the triangles are similar then the ratios of corresponding sides are equal, that is
[tex]\frac{AB}{DE}[/tex] = [tex]\frac{BC}{EF}[/tex] , substitute values
[tex]\frac{35}{5}[/tex] = [tex]\frac{42}{x}[/tex] ( cross- multiply )
35x = 210 ( divide both sides by 35 )
x = 6 → B
