Answer
$2 +2 \sqrt 3 \ i$
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=4 $ and $\theta= 60^{\circ}$
Therefore, $4 (\cos 60^{\circ} +i \sin 60^{\circ}) = 4(\dfrac{1}{2}+ i \dfrac{\sqrt 3}{2}) \\ = 2 +2 \sqrt 3 \ i$
