Question 144072
pi*r^2=A original
pi*(r+3)^2=A+100 new
pi(r^2+6r+9)=A+100
pi(r^2+6r+9)-100=A
pi(r^2+6r+9)-100=pi*r^2
r^2+6r+9-(100/pi)=r^2
6r+9-31.83=0
6r=22.83
r=3.81"
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Check:
pi*3.81^2=45.49
pi*6.81^2=145.49
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Ed