Answer
$-8 i$
Work Step by Step
The given complex number can be written in the rectangular form as follows: $r (\cos \theta +i \sin \theta) = a+i b$
Where, $a=r \cos \theta ; b =r \sin \theta $
We are given that $r=8 $ and $\theta= 270^{\circ}$
Therefore, $8 (\cos 270^{\circ} +i \sin 270^{\circ}) = 8(0 -1 i) \\ =-8 i$
