Recall that the circumference of a $\text{circle}=2\pi\left(\text{radius}\right)$.

$2\pi\left(3\ \text{inches}\right)=6\pi\approx18.84$ inches

Refer to the diagram from part (a) and recall that the $\text{circumference}=\pi\left(\text{diameter}\right)$.

$27\pi$
To get an appropriate decimal answer, round $\pi$ so that it equals $3.14$.