2008 AMC 8 Problem 25
Attempt Problem 25 of the 2008 AMC 8 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2008 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
25.
Margie’s winning art design is shown. The smallest circle has radius inches, with each successive circle’s radius increasing by inches. Approximately what percent of the design is shaded?
Answer: A
Small hint:
The total design area is the area of the largest circle.
Big hint:
The shaded regions are alternating disks or annuli with radii increasing by
Solution:
The largest circle has radius , so the entire design has area .
The shaded parts have areas , , and .
The total shaded area is , so the shaded fraction is , which is about .
Thus, A is the correct answer.
Problem 25 in other years
- 1985 AMC 8
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