If circle A has a radius of 6 millimeters, with a circumference of approximately 38 millimeters, and circle B has a radius of 60 millimeters, then what is circle B ’s approximate circumference?

Answer 1

The circumference of a circle can be calculated using the formula:

\[ C = 2 \pi r \]

where \( C \) is the circumference and \( r \) is the radius of the circle.

For circle A, with a radius of 6 millimeters:

\[ C_A = 2 \pi \times 6 \approx 12 \pi \approx 37.68 \text{ mm} \]

which is approximately 38 millimeters, as given.

For circle B, with a radius of 60 millimeters:

\[ C_B = 2 \pi \times 60 = 120 \pi \]

Approximating \( \pi \) as 3.14, we get:

\[ C_B \approx 120 \times 3.14 = 376.8 \text{ mm} \]

Thus, the approximate circumference of circle B is:

\[ \boxed{376.8} \text{ mm} \]