Olympiad workbookIOQMProperties of Triangles
Let A B C be an acute-angled triangle and let H be its orthocentre. Let G₁, G₂ and G₃ be the centroids of the triangles HBC , HCA and HAB respectively. If the area of triangle G ₁ G ₂ G ₃ is 7 units, what is the area of triangle A B C ?
Correct answer
63
Step-by-step solution
A B=2 D E ....(i) In H G ₁ G ₂ & HDE HG ₁ HD = G ₁ G ₂ DE = 2 3 G ₁ G ₂= 2 3 DE = 2 3 ( AB 2 )= AB 3 Becomes G ₁ G ₂ G ₃ ABC Area of A B C Area of G₁ G₂ G₃ = (A B)^2 (G₁ G₂ )^2 = ( A B G₁ G₂ )^2= ( 3 1 )^2 Area of ABC =9 ( . Area of . G ₁ G ₂ G ₃ ) Area of ABC =9 7=63