If z = 4+i3, then |z| = ?
\(\begin{array}{rcrcl} \boxed{~ z = a+ib \qquad |z| = \sqrt{a^2+b^2} ~} \end{array}\)
\(\begin{array}{rcrcl} z &=& 4+i\cdot 3 \\ |z| &=& \sqrt{4^2+3^2}\\ |z| &=& \sqrt{25}\\ |z| &=& 5 \end{array}\)