Answer:
AC = 7.5 cm
Step-by-step explanation:
Given that the triangles are similar then the ratios of corresponding sides are equal, that is
[tex]\frac{AC}{DE}[/tex] = [tex]\frac{BC}{DE}[/tex] , substitute values
[tex]\frac{AC}{3.5}[/tex] = [tex]\frac{7+8}{7}[/tex] , that is
[tex]\frac{AC}{3.5}[/tex] = [tex]\frac{15}{7}[/tex] ( cross- multiply )
7AC = 52.5 ( divide both sides by 7 )
AC = 7.5 cm
