Answer
$\color{blue}{3\sqrt{2}\ \text{cis}\ 45^\circ,\ 3\sqrt{2}\ \text{cis}\ \pi/4}$
Work Step by Step
$z=3+3i = x+iy \implies x=3, y=3$
$\Huge\cdot$ modulus: $\quad r = \sqrt{x^2+y^2} = \sqrt{3^2+3^2}= \sqrt{2(9)} = 3\sqrt{2}$
$\Huge\cdot$ argument: $\quad \tan\theta = y/x=3/3=1 \implies \theta = 45^\circ \equiv \pi/4$ (smallest positive real angle $\theta$ from $+x$-axis to graph of $z$)
$\begin{array}{|c|c|c|} \hline
\text{Standard} & \text{Trigonometric} & \text{Trigonometric} \\
\text{Form} & \text{Form (deg)} & \text{Form (rad)} \\ \hline
3+3i & 3\sqrt{2}\ \text{cis}\ 45^\circ & 3\sqrt{2}\ \text{cis}\ \pi/4 \\ \hline
\end{array}$
