Question 1106185
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You are given for the radius R(t) = t, where "t" is time in seconds.


The area of the circle is A(t) = {{{pi*(R(t))^2}}} = {{{pi*t^2}}}.


The rate of change of the circle’s area is  {{{(dA)/(dt)}}} = {{{2*pi*t}}}.


At t = 4 seconds,  {{{(dA)/(dt)}}} = {{{2*pi*4}}} = {{{2*3.14*4}}} = 25.12 m^2/s.
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Solved.