2022 AMC 10A Problems/Problem 21

Revision as of 13:17, 12 November 2022 by Kingravi (talk | contribs) (Solution)

Problem

A bowl is formed by attaching four regular hexagons of side 1 to a square of side 1. The edges of adjacent hexagons coincide, as shown in the figure. What is the area of the octagon obtained by joining the top eight vertices of the four hexagons, situated on the rim of the bowl?


2022 AMC10A 21 Figure.png

$\textbf{(A) }6\qquad\textbf{(B) }7\qquad\textbf{(C) }5+2\sqrt{2}\qquad\textbf{(D) }8\qquad\textbf{(E) }9$

Solution

Note that the octagon is equiangular by symmetry, but it is not equilateral. $4$ of it's sides are shared with the hexagon's sides, so each of those sides have side length $1$. However, the other $4$ sides are touching the triangles, so we wish to find the length of these sides.

Solution in Progress ~KingRavi

Video Solution By ThePuzzlr

https://youtu.be/br11LJJD4-c

~ MathIsChess

Video Solution by OmegaLearn using Equiangular Hexagon Properties

https://youtu.be/-QHhR2r9HgQ

~ pi_is_3.14

See Also

2022 AMC 10A (ProblemsAnswer KeyResources)
Preceded by
Problem 23
Followed by
Problem 25
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

The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. AMC logo.png