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| Question 42824:  Hi! I'm trying to figure out a problem with a hexagon. I need to find the side of a regular hexagon if the it is 18 inches apart from midpoint to midpoint. Any help would be greatly appreciated!
 Thankyou!
 Found 2 solutions by  fractalier, psbhowmick:
 Answer by fractalier(6550)
      (Show Source): 
You can put this solution on YOUR website! You can use trig to do this... Make a triangle with the segment connecting the midpoints of the sides as the base...
 Then bisect the top angle and drop an altitude, making two right triangles...
 Each right triangle has a top angle of 67.5 degrees...the long leg is 9, which is half of the 18...the hypotenuse is half the side of the hexagon...
 Thus sin 67.5 = 9/x and
 x = 9 / (sin 67.5) = 9.74
 and the side is double that, or about
 19.48 inches
Answer by psbhowmick(878)
      (Show Source): 
You can put this solution on YOUR website! Your statement of the problem is not very clear. I assume, what you meant is: The side of a regular hexagon in which the distance between the opposite sides is 18".
 
 See the regular hexagon ABCDEF below.
 
   
 According to the problem the distance between sides AB & DE, BC & EF and CD & FA is 18" and we are required to find length AB or any other side.
 
 Join B and F with a straight line. Then drop a perpendicular to BF from A intersecting BF at G.
 
 
   
 Now, in triangle ABF,
 BF = 18",
 < BAF =
  [since each internal angle of a regular hexagon is  ] 
 Clearly, triangle ABG and triangle AFG are congruent.
 So, < BAG =
  < BAF =  and BG =  BF = 9". 
 Now, in triangle ABG,
 < AGB =
  [since AG is perpendicular to BF] So in right angled triangle AGB,
 sin(< BAG) =
  or sin
  =  or AB =
  " =  " =  " = 10.4" (approx) 
 Thus the reqd. side of the regular hexagon is approximately 10.4 inches.
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