Respuesta :

check the picture below.

[tex]\bf 5i\implies \stackrel{a}{0}~~\stackrel{b}{+5}i\implies \stackrel{\stackrel{absolute~value}{modulus}}{r=\sqrt{a^2+b^2}}\implies r=\sqrt{0^2+5^2}\implies r=5[/tex]
Ver imagen jdoe0001