The radius of a circle is increasing at the rate of 0.7 cm/sec. What is the rate of increase of its circumference?

Explanation

To solve the problem step by step, we can follow these instructions:

### Step 1: Understand the given information
We know that the radius of a circle is increasing at a rate of 0.7 cm/sec. This means we can denote the rate of change of the radius with respect to time as:
\[ \frac{dR}{dt} = 0.7 \text{ cm/sec} \]

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