Three 6 0 ∘ -sectors of a unit circle pack neatly inside an equilateral triangle.
The side length of this triangle can be written as A + C B , where A , B , C are integers with C square-free.
What is the value of A + B + C ?
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Can we rearrange the sectors because given its equilateral triangle and sectors also of 60° ?
Why 1 + 2/√3 equals 1+2+3?🤔 Need help
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The problem says the side length is in the form of A + C B and is asking for A + B + C .
The exact side length is 1 + 3 2 so the answer is 1 + 2 + 3 = 6 .
"The area can be written as..." please change area to side length, or it is quite confusing.
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Thanks. Thinking of several problems simultaneously.
Which meaning of "soon" were you thinking of? >:-]
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lol. Two posted solutions are better than or equivalent to mine. I have nothing to add.
The y-coordinates of the 3 apexes are 0, 1 and cos 60°. Their mean must be the center of the triangle, 3 1 + 2 1 3 , so the height of the triangle is 3 times this h = 1 + 2 1 3 , and the side s = 3 2 h = 3 2 + 1 , so the answer is 1+2+3=6
Since i think noone has managed to over-complicate things as much as i usually do, here's how i solved this:
Since EGN is a sector of a unit circle, EK = 1, and since ∠ N E G = 6 0 ∘ then ∠ A E K = 3 0 ∘ , and AE = 2 * AK. Using Pythagoras, 3 × A K 2 = E K 2 = 1 so A K = 3 1 . Since AE = 2 * AK, A E = 3 2 .
Due to symmetry, B F = C D = A E = 3 2 . And C J = C D − D J = 3 2 − 1 .
Extending FL until it meets BC at P, we have ∠ L D P = ∠ M D J = 6 0 ∘ . Since ABC is equilateral, then ∠ A B C = 6 0 ∘ , and since ∠ B F P = ∠ H F L = 6 0 ∘ then ∠ F P B = ∠ L P D = 6 0 ∘ , therefore the LPD triangle is also equilateral.
Thus B C = B P + C D − D P = B F + C D − ( F P − F L ) = 3 2 + 3 2 − ( 3 2 − 1 ) = 1 + 3 2 . So A = 1 , B = 2 , C = 3 , and A + B + C = 6 .
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Label the points as shown below, and draw E F as the bisector of the sector and also draw B C .
Since △ A B C is a unit equilateral triangle, B C = 1 , and since D E = B C , D E = 1 .
As a radius of the sector, E F = 1 , and as a bisector of the 6 0 ° angle, ∠ F E G = 3 0 ° , and as a tangent, ∠ E F G is a right angle. Therefore E G = cos 3 0 ° 1 = 3 2 .
The side length D G is therefore D E + E G = 1 + 3 2 , so A = 1 , B = 2 , and C = 3 , and A + B + C = 6 .