Difference between revisions of "2025 AMC 8 Problems/Problem 12"

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==Problem==
 
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?
 
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?
  
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==Solution==
 
==Solution==
  
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 <math>8</math> points. The distance from the center to one of these <math>8</math> points can be found with the Pythagorean Theorem: <math>r^2 = 2^2 + 1^2 \rightarrow r = \sqrt5</math>. Therefore, the area of this circle = <math>\pi(r^2) = \boxed{\text{(C)\ 5pi\}}</math>.
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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 <math>8</math> points. The distance from the center to one of these <math>8</math> points can be found with the Pythagorean Theorem: <math>r^2 = 2^2 + 1^2 \rightarrow r = \sqrt5</math>. Therefore, the area of this circle = <math>\pi (\sqrt{5^2}) = \boxed{\textbf{(C)} 5\pi}</math>.
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~Soupboy0
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==Video Solution 1 by SpreadTheMathLove==
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https://www.youtube.com/watch?v=jTTcscvcQmI
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==Video Solution by Thinking Feet==
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https://youtu.be/PKMpTS6b988
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==See Also==
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{{AMC8 box|year=2025|num-b=11|num-a=13}}
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{{MAA Notice}}

Latest revision as of 20:12, 30 January 2025

Problem

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?

[asy] import graph;  size(100);  pen gridPen = black;  void drawSquare(pair p) {     draw(box(p, p + (1,1)), gridPen); }  int[][] grid = {     {0, 0, 0, 0, 0, 0},     {0, 0, 1, 1, 0, 0},     {0, 1, 1, 1, 1, 0},     {1, 1, 1, 1, 1, 1},     {1, 1, 1, 1, 1, 1},     {0, 1, 1, 1, 1, 0},     {0, 0, 1, 1, 0, 0},     {0, 0, 0, 0, 0, 0} };  int rows = grid.length; int cols = grid[0].length;  for (int i = 0; i < rows; ++i) {     for (int j = 0; j < cols; ++j) {         if (grid[i][j] == 1) {             drawSquare((j, rows - i - 1));         }     } } [/asy]

$\textbf{(A)}\ 3\pi\qquad \textbf{(B)}\ 4\pi\qquad \textbf{(C)}\ 5\pi\qquad \textbf{(D)}\ 6\pi\qquad \textbf{(E)}\ 8\pi$


Solution

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. The distance from the center to one of these $8$ points can be found with the Pythagorean Theorem: $r^2 = 2^2 + 1^2 \rightarrow r = \sqrt5$. Therefore, the area of this circle = $\pi (\sqrt{5^2}) = \boxed{\textbf{(C)} 5\pi}$.

~Soupboy0

Video Solution 1 by SpreadTheMathLove

https://www.youtube.com/watch?v=jTTcscvcQmI

Video Solution by Thinking Feet

https://youtu.be/PKMpTS6b988

See Also

2025 AMC 8 (ProblemsAnswer KeyResources)
Preceded by
Problem 11
Followed by
Problem 13
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
All AJHSME/AMC 8 Problems and Solutions

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