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| Question 969785:  Each side of the squares equals to 7units.
 How do I calculate the area of an equilateral triangle inside the square with sides 7units?
 How do I work out the area of a circle inside a square with sides equal to 7 units?
 What would the ratio be of area of triangle:area of circle?
 Answer by KMST(5328)
      (Show Source): 
You can put this solution on YOUR website! EQUILATERAL TRIANGLE: The area of a triangle with sides of lengths
  ,  , and  , opposite angles of measures
  ,  , and  , can be calculated as
  : 
  In the case of an equilateral triangle,
 all sides have the same length,
  , and all angles measure
  , so
   . 
 If your equilateral triangle inside a square looks like this
  , then
  and   . 
   . However, it may not be the expected answer,
 but you may be able to fit a slightly larger triangle if you "tilt" it,
 like this
  . 
 CIRCLE:
 The larges circle that you would be able to fit inside a square has a diameter as long as the side of the square:
 
  If the square side length is  , the circle radius is  The area of a circle of radius
  , so a circle of radius
  . In particular, for
  the area would be
   . 
 For the triangle and circle described above,
 the ratio of their areas would be
 
   . (The side of the square
  did not matter, as long as we use the same square size to fit the triangle and the circle). 
 LARGER TRIANGLE:
 
  In the right triangle corners, according to the Pythagorean theorem, 
  and  , so 
  
  
  
  
  
  , and since  and  
  
  
  , and  . Now, we knew that for a triangle,
  , and that this tilted triangle has
  , so
  and   . That makes the area of thte tilted triangle
 approximately
  , and the ratio of areas for the tilted triangle and circle would be
 
  . That ratio is approximately
  .
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