How do I find the modulus of a complex number?

What features should I know about the modulus of a complex number?

How do I find the argument of a complex number?

• The argument of a complex number is the?angle?that it makes on an?Argand diagram
  • The angle must be taken from the?positive real axis
  • The angle must be in a?counter-clockwise?direction
• Arguments can be calculated using right-angled?trigonometry
  • This involves using the tan ratio plus a sketch to decide whether it is positive/negative and acute/obtuse

What features should I know about the argument of a complex number?

What are the rules for moduli and arguments under multiplication and division?