Correct Answer: Option D

Explanation

A = \(\pi\)r², \(\frac{\delta A}{\delta r}\) = 2πr

So, using \(\frac{\delta A}{\delta t}\) = \(\frac {\delta A}{\delta r}\) x \(\frac {\delta A}{\delta t}\)

= 2\(\pi\)r x 0.02

= 2\(\pi\) x 7 x 0.02

= 2 x \(\frac{22}{7}\) x 0.02

= 0.88cm²s^-1

There is an explanation video available below.

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