Here is the way you would go about these questions. I will complete questions 1 and 3, as well as 7. Seeing the way these questions are solved, I am confident you can complete the rest.
1. The image is telling us that the circle's radius is 3 inches. To find the perimeter using radius, multiply the radius by two to get the full diameter. Then, multiply by π (3.14 in your case).
3 x 2 = 6 inches (diameter= 6 inches)
c=πd
c= 3.14 x 6
c=18.84 inches
∴The circumference is 18.84 inches.
3. The image is telling us that the diameter is 8 feet.
c=πd
c=3.14 x 8
c=25.12 feet.
∴The circumference of the circle is 25.12 feet.
7. This image is a semi-circle, which means that you may find the full diameter and divide by 2 (for half of the full circle).
c=πd
c=3.14 x 23
c=72.22 cm
72.22 ÷ 2= 36.11
∴The circumference 36.11 cm.