A triangle's angles are: , , and . We drop perpendiculars from the midpoints of the sides as is shown the figure below.
If the area of the blue hexagon is , and the area of the triangle is , then find the value of .
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Segments D E , E F , D F divide △ A B C into four congruent triangles. Points G , H , I area orthocentres of triangles E F A , E D C , D F B respectively. Hexagon E H D I F G can be divided into four triangles: D E F , E F G , E D H , D F I . Area of △ D E F is 4 1 of the area of △ A B C . Triangles E F G , E D H , D F I make up the area of whole congruent triangle i.e. E F A as their vertices are made up of orthocentre and each pair of the reference triangle sides. This means that hexagon area is equal to areas of two smaller triangles like that of D E F and E F A which in turn is half of the area of triangle A B C . The answer is 2 1 .
Note:
1) All vertices of the hexagon lie on the nine-point circle of the large triangle.
2) The ratio is the same regardless of the angle measures.