The dashed line labeled as 6 is the diameter of the circular part of the figure.
The circumference of a circle is it's perimeter, so we need to find half the circumference first.
The formula for circumference is PI x diameter, since we need half we will divide the total circumference by 2.
Circumference = 3.14 x 6 = 18.85 / 2 = 9.425
Now we add that to the other 3 dimensions for total perimeter:
9.425 + 9 + 9 +6 = 33.425
You may need to round the answer, you didn't say if it needed to be rounded a certain way.