In the image, you're asked to find the circumference of two circles, given the radius for each. Let's go through the process for both:

Formula for Circumference:

The circumference $C$ of a circle is calculated by: $C = 2\pi r$ where $r$ is the radius of the circle.

Problem 9:

• Radius $r = 8 \, \text{mi}$ $C = 2\pi(8) = 16\pi \approx 16 \times 3.1416 = 50.27 \, \text{mi}$ So, the circumference is approximately 50.3 miles (rounded to the nearest tenth).

Problem 10:

• Radius $r = 8.3 \, \text{yd}$ $C = 2\pi(8.3) = 16.6\pi \approx 16.6 \times 3.1416 = 52.15 \, \text{yd}$ So, the circumference is approximately 52.2 yards (rounded to the nearest tenth).

Would you like more details or have any questions about the calculations?

Related Questions:

1. What is the relationship between the diameter and the circumference of a circle?
2. How does the circumference change if the radius is doubled?
3. Can you find the area of a circle if you are given the circumference instead of the radius?
4. What units should you use for circumference if the radius is given in meters?
5. How would you calculate the circumference if the radius was given as a fraction or a decimal?

Tip:

Always use the most accurate value of $\pi$ available to ensure precision in your calculations!