Answer:
DE = 17.5 cm
Step-by-step explanation:
Since the triangles are similar then the ratios of corresponding sides are in proportion , that is
[tex]\frac{DE}{BC}[/tex] = [tex]\frac{AE}{AC}[/tex] ( substitute values )
[tex]\frac{DE}{12.5}[/tex] = [tex]\frac{15+6}{15}[/tex] = [tex]\frac{21}{15}[/tex] ( cross- multiply )
15 DE = 262.5 ( divide both sides by 15 )
DE = 17.5 cm
