A bakery charges for a cookie that is 2 inches in diameter. If the price is proportional to the area, how much do they charge for an extra large cookie that is inches in diameter? Assume that each cookie is shaped of a circle.

Question

A bakery charges  for a cookie that is 2 inches in diameter. If the price is proportional to the area, how much do they charge for an extra large cookie that is  inches in diameter? Assume that each cookie is shaped of a circle.

anonymous · Answer

copy and paste fail

anonymous · Answer

sorry i was supposed to be $0.10 for a cookie that is 2 inches in diameter and an extra large cookie is 10 inches in diameter

anonymous · Answer

ohh sorry i get it now i have to multiply the 2 and the 0.10 by 5

phi · Answer

the long way is figure out the area of the small cookie, and write a ratio 
cost/area
then figure out the area of the big cookie, and write the ratio
x/area_big

set these ratios equal and solve for x (the unknown cost)

or,  because if you multiply the diameter by 5,  you will multiply the area by 5^2,  the cost will also be multiplied by 5^2

anonymous · Answer

thanks