CBSE BOARD X, asked by raj31144131, 11 months ago

please answer my question

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Answered by Anonymous
7

I am proving by coordinate geometry .

If you want geometric proof do comment !


In Δ ABC ,

Let A be x₁ , y₁

Let B be x₂ , y₂

Let C be x₃ , y₃


Mid point formula says :

D = x = ( x₁ + x₂ ) / 2  , y = ( y₁ + y₂ ) / 2

E = x = ( x₂ + x₃ ) / 2 , y = ( y₂ + y₃ ) / 2

F = x  = ( x₁ + x₃ ) / 2 , y = ( y₁ + y₃ ) / 2


Centroid of Δ ABC


x = ( x₁ + x₂ + x₃ ) / 3

y = ( y₁ + y₂ + y₃ ) / 3


Centroid of Δ DEF


x = [ ( x₁ + x₂ ) / 2 + ( x₁ + x₃ ) / 2 + ( x₂ + x₃ ) / 2 ] / 3

= > x = [ x₁ / 2 + x₂ / 2 + x₁ / 2 + x₃ / 2 + x₂ / 2 + x₃ / 2 ] / 3

Use  a / 2 + a / 2 = a

= > x = [ x₁ + x₂ + x₃ ] / 3


Similarly :

y = [ ( y₁ + y₂ ) / 2 + ( y₁ + y₃ ) / 2 + ( y₂ + y₃ ) / 2 ] / 3

= > y = [ y₁ / 2 + y₂ / 2 + y₁ / 2 + y₃ / 2 + y₂ / 2 + y₃ / 2 ] / 3

Use  a / 2 + a / 2 = a

= > y = [ y₁ + y₂ + y₃ ] / 3


Hence the coordinates of the centroid of Δ ABC is the same as the centroid of Δ DEF.

Therefore it is the same point !

[ P.R.O.V.E.D ]

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