(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A stone dropped into a still pond sends out a circular ripple whose radius increases at a constant rate of 3 ft/s. How rapidly is the area enclosed by the ripple increasing at the end of 10 s?

2. Relevant equations

How do I even set up implicit differentiation?

3. The attempt at a solution

I know that dr/dt is 3 ft/s and that I'm looking for dA/dt, but I don't know where t = 10s goes into that equation, especially when I don't have the radius... Do I multiply time times dr/dt to get radius at 10 seconds and go from there?

HELP!!

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# Related rates: When t is given and r is not

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