In the problem statement, the radius of the circle is set and it is equal to R = 3.9 cm. To find the circumference, you need to know the value of the constant – the number n = 3.1 (as required by the problem statement).
We are looking for the length of a circle with a given radius.
We will search for the circumference using the following formula.
l = 2пR, where R is the radius of the circle, and we remembered the value of the number n above.
Substitute the known values into the formula and calculate the circumference:
l = 2 * 3.1 * 3.9 = 6.2 * 3.9 = 24.18 cm.
The length of a circle with a radius of R = 3.9 cm is 24.18 cm.
Answer: 24.18 cm.
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