For the answer to the question above, I'll show my solution for the answer below.
Area A = pi r^2 
<span>The rate of change of area = d A/ d t = 2 pi r d r/d t </span>
<span>r= 2t, d r = 2 d t </span>
<span>This gives </span>
<span>d A/ d t = 2 pi 2t 2 d t = 8 pi t dt </span>
<span>Integrate it </span>
<span>A= 4 pi t^2. </span>
<span>After t=5, the area will be 100* 3.14 square= 314 square units.</span>
        
                    
             
        
        
        
16 out of 64 is 25% hope this helped