Let z=x+iy be a complex number. The distance from this complex number to the origin is
[tex]\sqrt{(x-0)^2+(y-0)^2}=\sqrt{x^2+y^2}.[/tex]
Consider all options:
A. z=2+15i, then [tex]\sqrt{2^2+15^2}=\sqrt{229}.[/tex]
B. z=17+i, then [tex]\sqrt{17^2+1^2}=\sqrt{290}.[/tex]
C. z=20-3i, then [tex]\sqrt{20^2+(-3)^2}=\sqrt{409}.[/tex]
D. z=4-i, then [tex]\sqrt{4^2+(-1)^2}=\sqrt{17}.[/tex]
Answer: correct choice is D.
