Final answer:
To find the circumference of a circle with a radius of 10 cm using the formula C = 2πr, we calculate it as 20π cm, making option b) the correct choice.
Step-by-step explanation:
The formula for the circumference of a circle is given by C = 2πr, where 'C' represents the circumference and 'r' is the radius of the circle. To find the circumference when the radius r is 10 cm, we use this formula and plug in the given value for the radius.
The calculation step would be:
C = 2π(10 cm)
C = 20π cm
Since π (pi) is approximately 3.14159, if we need a numerical approximation of the circumference, we can multiply 20 by π to get the value in centimeters. However, the question seems to require the answer in terms of pi, therefore, the correct answer, represented in terms of π, would be 20π cm, which corresponds to option b) 20π cm.