question_id's blog

By question_id, history, 5 years ago, In English

I can figure out the short formula many contestant used and in TT(tutorial). Can anyone give me some explanation on this.. sketch etc. Thanks in Advance.

  • Vote: I like it
  • 0
  • Vote: I do not like it

5 years ago, # |
  Vote: I like it 0 Vote: I do not like it

I have tried it. But not finding clue and I am trying more on it.

5 years ago, # |
  Vote: I like it +3 Vote: I do not like it

Extend the sides of the hexagon to form an equilateral triangle (try to see why it is an equilateral triangle). Then the area of this triangle is sqrt(3)/4 * a^2 where a = a1 + a2 + a3 is the length of the side of the big triangle. Notice that the area of the original hexagon equals to the Area of big triangle - Area of 3 triangles ==> the area = sqrt(3)/4 * a^2 - sqrt(3)/4 * a1^2 - sqrt(3)/4 * a3^2 - sqrt(3)/4 * a5^2. where a1, a3, and a5 are the sides of the 3 triangles we added to the hexagon to form the big triangle.

Now to see how many triangles of side = 1 exists we divide the area of the hexagon by the area of an equilateral triangle of side length = 1 (which equals sqrt(3)/4) ==> the answer = a^2 - a1^2 - a3^2 - a5^2.