Please help me!! Iv been stuck!

Answer:
[tex]7[/tex]
Step-by-step explanation:
Because the leftmost triangle is a 45-45-90 isosceles right triangle, [tex]a = b =\frac{7\sqrt2}{\sqrt2} = 7\\[/tex]
The rightmost triangle is a 30-60-90 triangle, and the side lengths are in the proportion [tex]1:\sqrt3:2[/tex] from shortest to longest. Therefore, [tex]c = 7\cdot\frac{\sqrt3}{1} = 7\sqrt{3} \implies \boxed{7}[/tex]