Star in a Hexagon
Weekly Problem 20 - 2017
The diagram shows a design formed by drawing six lines in a regular hexagon. What fraction of the hexagon is shaded?
The diagram shows a design formed by drawing six lines in a regular hexagon. What fraction of the hexagon is shaded?
Image
![Star in a Hexagon Star in a Hexagon](/sites/default/files/styles/large/public/thumbnails/content-id-11689-Star%252520in%252520a%252520Hexagon%252520Stefania.png?itok=i0MVryli)
The diagram shows a design formed by drawing six lines in a regular hexagon. The lines divide each edge of the hexagon into three equal parts.
What fraction of the hexagon is shaded?
If you liked this problem, here is an NRICH task that challenges you to use similar mathematical ideas.
Answer: $\frac29$
Split each hexagon into 6 small triangles
Image
![Star in a Hexagon Star in a Hexagon](/sites/default/files/styles/large/public/thumbnails/content-id-11689-star%252520in%252520a%252520hexagon%2525201.png?itok=YOFFAtYT)
Image
![Star in a Hexagon Star in a Hexagon](/sites/default/files/styles/large/public/thumbnails/content-id-11689-star%252520in%252520a%252520hexagon%2525202.png?itok=kY0_VmVh)
Image
![Star in a Hexagon Star in a Hexagon](/sites/default/files/styles/large/public/thumbnails/content-id-11689-star%252520in%252520a%252520hexagon%2525203.png?itok=KEVHVAX_)
6$\times$6 + 6$\times$1 = 42 unshaded triangles
6$\times$1 + 1$\times$6 = 12 shaded triangles
Fraction shaded = $\dfrac{12}{42+12} = \dfrac{2}{7+2} =\dfrac29$