Answer
If $z = cos\theta + isin\theta$, then its absolute value $|z|$ = 1 (As proved in the step by step work)
Work Step by Step
If $z = cos\theta + isin\theta$, its absolute value $|z|$ will be,
= $\sqrt{cos^2\theta + sin^2\theta}$
= 1 (since according to Pythagorean identity, $cos^2\theta + sin^2\theta = 1$)
Hence, if $z = cos\theta + isin\theta$, then its absolute value $|z|$ = 1.
