Difference between revisions of "2021 Fall AMC 10B Problems/Problem 11"

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==Problem==
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==Problem 11==
 
A regular hexagon of side length <math>1</math> is inscribed in a circle. Each minor arc of the circle
 
A regular hexagon of side length <math>1</math> is inscribed in a circle. Each minor arc of the circle
 
determined by a side of the hexagon is reflected over that side. What is the area of the region
 
determined by a side of the hexagon is reflected over that side. What is the area of the region

Revision as of 22:03, 23 November 2021

Problem 11

A regular hexagon of side length $1$ is inscribed in a circle. Each minor arc of the circle determined by a side of the hexagon is reflected over that side. What is the area of the region bounded by these $6$ reflected arcs?

Solution

Let the hexagon described be of area $H$ and let the circle's area be $C$. Let the area we want to aim for be $A$. Thus, we have that $C-H=H-A$, or $A=2H-C$. By some formulas, $C=\pi{r}^2=\pi$ and $H=6\cdot\frac12\cdot1\cdot(\frac12\cdot\sqrt3)=\frac{3\sqrt3}2$. Thus, $A=3\sqrt3-\pi$ or $\boxed{(\textbf{B})}$.

~Hefei417, or 陆畅 Sunny from China

See Also

2021 Fall AMC 10B (ProblemsAnswer KeyResources)
Preceded by
Problem 10
Followed by
Problem 12
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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