gaokao 2020 Q3

gaokao · China · shanghai 4 marks Complex Numbers Arithmetic Modulus Computation

Given that the complex number $z$ satisfies $z = 1 - 2 i$ ($i$ is the imaginary unit), find $| z | =$ $\_\_\_\_$

$\sqrt { 5 }$

Given that the complex number $z$ satisfies $z = 1 - 2 i$ ($i$ is the imaginary unit), find $| z | =$ $\_\_\_\_$