How do you find abs(-8-4i)|84i|?

1 Answer
Aug 18, 2016

|-8-4i|=4sqrt5~=8.9444|84i|=458.9444.

Explanation:

For, z=x+iy in CC, |z|=sqrt(x^2+y^2).

Hence, |-8-4i|=sqrt((-8)^2+(-4)^2)=sqrt(64+16)=sqrt80=sqrt(4^2*5)=4sqrt5.

Taking, sqrt5~=2.2361, Reqd. Value~=4*2.2361=8.9444.