1. ## Circular Plot

The circumference of a circular plot of land is increased by 10%. What is the best estimate of the total percentage that the area of the plot increased?

(1) 10% (3) 25%
(2) 21% (4) 31%

2. Originally Posted by symmetry
The circumference of a circular plot of land is increased by 10%. What is the best estimate of the total percentage that the area of the plot increased?

(1) 10% (3) 25%
(2) 21% (4) 31%
final r=1.1
final r^2=1.21
hence change=.21=21%

3. ## Tell me...

Where did r=1.1 and r^2=1.21 come from?