How do you find the absolute value of #4-8i#?

1 Answer
Ratnaker Mehta
Jul 12, 2016

#|4-8i|=sqrt{4^2+(-8)^2}=sqrt(16+64)=sqrt80=4sqrt5.#

Taking, #sqrt5~=2.236, |z|~=4xx2.236=8.944#

Explanation:

Absolute Value or Modulus #|z|#of a Complex No. #z=x+iy# is defined by,

#|z|=sqrt(x^2+y^2).#

#|4-8i|=sqrt{4^2+(-8)^2}=sqrt(16+64)=sqrt80=4sqrt5#

Taking, #sqrt5~=2.236, |z|~=4xx2.236=8.944#

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