# Help with a math puzzle

• Sep 18th 2009, 03:05 PM
gymnastcheer33
Help with a math puzzle
I am struggling to figure out the answer to this question and the proper way to work the problem. Any help will be greatly appreciated. Please show me how to work the problem so that I may learn.

To make money for their club some college students held a bake sale. Herbert was assigned the correct pricing of cookies. A small cookie was to sell for 25¢. A giant cookie, whose diameter was four times that of the smaller cookie, was also to be sold. Herbert priced the giant cookie based on its area as compared to the area of the small cookie. What price did Herbert put on the giant cookie?
• Sep 18th 2009, 04:40 PM
skeeter
Quote:

Originally Posted by gymnastcheer33
I am struggling to figure out the answer to this question and the proper way to work the problem. Any help will be greatly appreciated. Please show me how to work the problem so that I may learn.

To make money for their club some college students held a bake sale. Herbert was assigned the correct pricing of cookies. A small cookie was to sell for 25¢. A giant cookie, whose diameter was four times that of the smaller cookie, was also to be sold. Herbert priced the giant cookie based on its area as compared to the area of the small cookie. What price did Herbert put on the giant cookie?

4 times the diameter is also increasing the radius by a factor of 4.

area of a circle is $\pi r^2$

increasing the radius by a factor of 4 ... $\pi(4r)^2$

how many times bigger in area?