Difference between revisions of "2007 AMC 10A Problems/Problem 15"
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== Problem == | == Problem == | ||
Four circles of radius <math>1</math> are each tangent to two sides of a square and externally tangent to a circle of radius <math>2</math>, as shown. What is the area of the square? | Four circles of radius <math>1</math> are each tangent to two sides of a square and externally tangent to a circle of radius <math>2</math>, as shown. What is the area of the square? |
Latest revision as of 17:26, 12 December 2020
Contents
Problem
Four circles of radius are each tangent to two sides of a square and externally tangent to a circle of radius , as shown. What is the area of the square?
Solution
Draw a square connecting the centers of the four small circles of radius . This square has a diagonal of length , as it includes the diameter of the big circle of radius and two radii of the small circles of radius . Therefore, the side length of this square is The radius of the large square has a side length units larger than the one found by connecting the midpoints, so its side length is The area of this square is
Solution 2
We draw the long diagonal of the square. This diagonal yields . We know that the side length in terms of the diagonal is , so our side length is . However, we are trying to look for the area, so squaring yields
See Also
2007 AMC 10A (Problems • Answer Key • Resources) | ||
Preceded by Problem 14 |
Followed by Problem 16 | |
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 AMC 10 Problems and Solutions |
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