The modulus of $ z $ is:
$$ |z| = 0.184$$To find modulus of a complex number $ z = a + bi $ we use formula:
$$ |z| = \sqrt{a^2 + b^2} $$In this example we have $ a = 0.1706 $ and $ b = \frac{ 6881 }{ 100000 } $ so:
$$ \begin{aligned}|z| &= \sqrt{ 0.1706^2 + \left(\frac{ 6881 }{ 100000 }\right)^2 } \\[1 em]|z| &= \sqrt{ 0.0291 + \frac{ 47348161 }{ 10000000000 } } \\[1 em]|z| &= \sqrt{ 0.0339 } \\[1 em]|z| &= 0.184 \\[1 em] \end{aligned} $$