As $t$ Varies, the Equations $x=2+6 \cos t$ And $y=-3+6 \sin t$ Trace Out a Circle

Short Answer

As $t$ varies, the equations $x=2+6 \cos t$ and $y=-3+6 \sin t$ trace out a circle.
a) Describe the center and radius of the circle.
b) If $0 \leq t \leq \frac{\pi}{2}$ , what part of the circle is obtained?