Answer: The answer is (a) 15.
Step-by-step explanation: We are given a figure with two similar triangles with sides of lengths x, 15 and corresponding sides of lengths 15 and 25 respectively.
Since the given triangles are similar, so their sides will be proportional.
Therefore, we have
[tex]\dfrac{x}{9}=\dfrac{25}{15}\\\\\\\Rightarrow \dfrac{x}{9}=\dfrac{5}{3}\\\\\\\Rightarrow x=\dfrac{5\times 9}{3}\\\\\Rightarrow x=15.[/tex]
Thus, the value of x is 15.
