Chapter 6 - Section 6.5 - Complex Numbers in Polar Form; DeMoivre's Theorem - Exercise Set - Page 767: 4

$$|z|=4$$

We plot the complex number $z=4$ the same way we plot $(4,0)$ in the rectangular coordinate system. We find the absolute value of the complex number as follows.$$|z|=|a+bi|=\sqrt{a^2+b^2} \\ \Rightarrow \quad |z|=|4+0i|=\sqrt{4^2+0^2}=4$$