AMC 8 2025 Problem 12

AMC8 2025 年第 12 题

圆★★★☆☆
The region shown below consists of 24 squares, each with side length 1 centimeter. What is the area, in square centimeters, of the largest circle that can fit inside the region, possibly touching the boundaries?
下图所示区域由24个边长为1厘米的正方形组成。请问该区域内正好能够容纳的最大圆的面积是多少平方厘米?(最大圆可能会接触到边界)
AMC 8 2025 Problem 12 figure
  1. A.3π3\pi
  2. B.4π4\pi
  3. C.5π5\pi
  4. D.6π6\pi
  5. E.8π8\pi

正确答案 · Correct Answer

C

解析 · Solution

Solution 1

The largest circle that can fit inside the figure has its center in the middle of the figure and will be tangent to the figure in 8 points. By the Pythagorean Theorem, the distance from the center to one of these 8 points is 22+12=5\sqrt{2^2 + 1^2} = \sqrt5, so the area of this circle is 𝜋 5 2 = (C) 5 𝜋. LaTeX\LaTeXeditsbyiamnotsukatmath(saharshdevaraju08:04,7November2025(EST)saharshdevaraju)edits by i_am_not_suk_at_math (saharshdevaraju 08:04, 7 November 2025 (EST)saharshdevaraju)

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