Let denote a triangle with area .
Triangle if formed by taking medians of the triangle as side lengths.
Let the area of this triangle thus formed be .
Find .
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A i and A i − 1 are related by the formula A i = 4 3 A i − 1
Thus i = 0 ∑ ∞ A i = A 0 n = 0 ∑ ∞ ( 4 3 ) n = 4 A 0
Proof that A i = 4 3 A i − 1
□ B G C G ′ is a parallelogram with sides 2 β , 2 γ , 2 β , 2 γ , Thus area of △ G G ′ C is equal to the area of △ B G C
Now let the area of triangle with sides α , β , γ be Δ .
Thus area of △ G G ′ C which has sides 2 α , 2 β , 2 γ is 4 Δ , Thus area of △ B G C is 4 Δ ( I f s i d e s a r e s c a l e d b y a f a c t o r o f k a r e a s a r e s c a l e d b y a f a c t o r o f k 2 )
By similar reasoning, we can say areas of △ B G C △ C G A & △ A G B are all 4 Δ .
Thus area of △ A B C is 1 2 Δ
Also, the medians have lengths 3 α , 3 β , 3 γ , Thus the triangle formed by the medians will have an area of 9 Δ
Thus the area of triangle Δ A = 1 2 Δ .
And the area of the triangle formed by medians Δ M = 9 Δ .
Thus we get the relation Δ M = 4 3 Δ A .