Answer:
A
Step-by-step explanation:
Since the triangles are similar then the ratios of corresponding sides are equal, that is
[tex]\frac{LM}{QR}[/tex] = [tex]\frac{KL}{PQ}[/tex] , substitute values
[tex]\frac{x}{15}[/tex] = [tex]\frac{28}{21}[/tex] ( cross- multiply )
21x = 420 ( divide both sides by 21 )
x = 20 → A
