The radius of the circle has increased from 4 decimeters to 6 centimeters, and the area of the circle has increased by () square centimeters a, 6b, 20c, 20c

C
According to the area formula of circle, area s = π × R & sup2;
The increased area is π × 6 & sup2; - π × 4 & sup2; = 20 π

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