Answer:
x = 8
Step-by-step explanation:
Since the triangles are similar then the ratios of corresponding sides are equal, that is
[tex]\frac{BC}{DC}[/tex] = [tex]\frac{AC}{EC}[/tex], substitute values
[tex]\frac{x}{10}[/tex] = [tex]\frac{12}{15}[/tex] ( cross- multiply )
15x = 120 ( divide both sides by 15 )
x = 8
