Answer
$\frac{25}{\pi}$
Work Step by Step
Step 1 When a 10-unit distance is measured along the $z$-axis, $0.2\theta = 10 \implies \theta = 50$. For $\theta = 2\pi$, the helix makes one revolution. Thus, it makes $\frac{50}{2\pi} = \frac{25}{\pi}$ revolutions. Result $\frac{25}{\pi}$