Mathematics

Problem

A circular parchment is being unrolled so that its radius increases at

2\,\text{cm}/\text{s}

. When the radius is

5\,\text{cm}

, how fast is the area of the parchment increasing? a)

50\pi\,\text{cm}^2/\text{s}

20\,\text{cm}^2/\text{s}

20\pi\,\text{cm}^2/\text{s}

10\pi\,\text{cm}^2/\text{s}