Think about 3-D shapes.
Eight equilateral triangles would form two square based pyramids stuck together.
Count all the lines of the shape.
It will have twelve lines which would be enough lines for twelve matchsticks.
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In an octagon, there are 20 equilateral triangles. Each side of the octagon can form two equilateral triangles with the adjacent sides, resulting in 8 equilateral triangles. Additionally, the diagonals of the octagon can form 12 more equilateral triangles. Therefore, the total number of equilateral triangles in an octagon is 8 + 12 = 20.
1~Tetrahedron *4 faces (made of equilateral triangles) *6 edges *5 vertices 2~Hexahedron (cube) *6 faces (made of squares) *12 edges *8 vertices 3~Octrahedron *8 faces (made up of equilateral triangles) *12 edges *6 vertices 4~Icosahedron *20 faces (made of equilateral triangles) *30 edges *12 verticies 5~Dodecahedron *12 faces (made of pentagons) *30 edges *20 vertices.
1:2
There are 2160 degrees 1n a 14-gon and 180 degrees in a triangle and 2160/180 = 12. Answer: 12 triangles
12