If a large pizza has a radius that is 10% larger that that of a medium pizza, what is the percent increase in area between a medium and a large pizza?  Choose the correct choice from the following.
A) 15%	B) 21%	C) 25%	D) 30%	E) 36%
Let the radius of medium pizza be r. Then the radius of large pizza is 1.1r.   The area of the medium pizza is pi*r^2   The area of the large pizza is pi*(1.1*r)^2 = 1.21*pi*r^2, an increase of 21%.   The answer is 21%.
<result>B</result>
If a large pizza has a radius that is 10% larger that that of a medium pizza, what is the percent increase in area between a medium and a large pizza?