The ratio of the circumferences of two circles is 2:3. If the large circle has a radius of 39 cm, what is the radius of the small circle?

A circle’s circumference is proportional to its radius because C = 2πr. The small-to-large radius ratio is therefore 2:3, so the small radius is (2/3) × 39 = 26 cm. The correct choice is 26 cm.

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