Answer:
v = √(z(w+z))
Explanation:
Right triangles in this configuration are all similar. That means the side ratios are proportional, so ...
long side/hypotenuse = z/v = v/(w+z)
Multiplying this equation by the product of the denominators, we have ...
z(w+z) = v²
Taking the square root gives ...
v = √(z(w+z)) . . . . . . matches the last selection