Answer:
x = 5
Step-by-step explanation:
The small right triangle and the outer right triangle are similar, thus ratios of corresponding sides are equal, that is
[tex]\frac{3.5}{7}[/tex] = [tex]\frac{2.5}{x}[/tex] ( cross- multiply )
3.5x = 17.5 ( divide both sides by 3.5 )
x = 5
