Can someone help please :)

Answer:
x = 5
Step-by-step explanation:
These triangles are similar, so they are in proportion to each other. Because of this we can say [tex]\frac{2.5}{3.5}[/tex] (the lengths of the vertical sides) = [tex]\frac{x}{7}[/tex] (the lengths of the hypotenuses). If we solve by cross-multiplying the numbers and then dividing we get x = 5.