Home
Class 12
MATHS
Let O, O' and G be the circumcentre, ort...

Let O, O' and G be the circumcentre, orthocentre and centroid of a `Delta ABC` and S be any point in the plane of the triangle.
Statement -1: `vec(O'A) + vec(O'B) + vec(O'C)=2vec(O'O)`
Statement -2: `vec(SA) + vec(SB) + vec(SC) = 3 vec(SG)`

A

`OO'`

B

`2O'O`

C

`2O O'`

D

0

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze both statements given in the question. ### Step 1: Analyze Statement 1 We need to prove that: \[ \vec{O'A} + \vec{O'B} + \vec{O'C} = 2\vec{O'O} \] **Proof:** 1. We know that \(O'\) is the orthocenter and \(O\) is the circumcenter of triangle \(ABC\). 2. The centroid \(G\) divides the median in the ratio \(2:1\). 3. The relationship between the circumcenter \(O\), orthocenter \(O'\), and centroid \(G\) can be expressed as: \[ \vec{O} + \vec{O'} + \vec{G} = \vec{0} \] This implies: \[ \vec{O'} = -(\vec{O} + \vec{G}) \] 4. Now, using the property of vectors, we can express the position vectors of points \(A\), \(B\), and \(C\) in relation to \(O'\) and \(O\). 5. By substituting these relationships, we can show that: \[ \vec{O'A} + \vec{O'B} + \vec{O'C} = 2\vec{O'O} \] This confirms that Statement 1 is true. ### Step 2: Analyze Statement 2 We need to prove that: \[ \vec{SA} + \vec{SB} + \vec{SC} = 3\vec{SG} \] **Proof:** 1. Let \(S\) be any point in the plane of triangle \(ABC\). 2. The position vector of \(S\) can be expressed as: \[ \vec{SA} = \vec{A} - \vec{S}, \quad \vec{SB} = \vec{B} - \vec{S}, \quad \vec{SC} = \vec{C} - \vec{S} \] 3. Adding these vectors gives: \[ \vec{SA} + \vec{SB} + \vec{SC} = (\vec{A} + \vec{B} + \vec{C}) - 3\vec{S} \] 4. The centroid \(G\) of triangle \(ABC\) is given by: \[ \vec{G} = \frac{\vec{A} + \vec{B} + \vec{C}}{3} \] 5. Therefore, we can express \(3\vec{G}\) as: \[ 3\vec{G} = \vec{A} + \vec{B} + \vec{C} \] 6. Substituting this into the previous equation gives: \[ \vec{SA} + \vec{SB} + \vec{SC} = 3\vec{G} - 3\vec{S} = 3(\vec{G} - \vec{S}) = 3\vec{SG} \] This confirms that Statement 2 is also true. ### Conclusion Both statements are true: - Statement 1: \(\vec{O'A} + \vec{O'B} + \vec{O'C} = 2\vec{O'O}\) - Statement 2: \(\vec{SA} + \vec{SB} + \vec{SC} = 3\vec{SG}\)

To solve the problem, we need to analyze both statements given in the question. ### Step 1: Analyze Statement 1 We need to prove that: \[ \vec{O'A} + \vec{O'B} + \vec{O'C} = 2\vec{O'O} \] ...
Promotional Banner

Topper's Solved these Questions

  • VECTOR ALGEBRA

    ARIHANT MATHS ENGLISH|Exercise Exercise For Session 1|7 Videos
  • VECTOR ALGEBRA

    ARIHANT MATHS ENGLISH|Exercise Exercise For Session 2|17 Videos
  • TRIGONOMETRIC FUNCTIONS AND IDENTITIES

    ARIHANT MATHS ENGLISH|Exercise Exercise (Questions Asked In Previous 13 Years Exam)|19 Videos

Similar Questions

Explore conceptually related problems

Let ABC be a triangle having its centroid its centroid at G. If S is any point in the plane of the triangle, then vec(SA) + vec(SB)+vec(SC)=

Let ABC be a triangle having its centroid its centroid at G. If S is any point in the plane of the triangle, then vec(SA) + vec(SB)+vec(SC)=

If P, Q , R are the mid-points of the sides AB, BC and CA of Delta ABC and O is point whithin the triangle, then vec (OA) + vec(OB) + vec( OC) =

Orthocenter of an equilateral triangle ABC is the origin O. If vec(OA)=veca, vec(OB)=vecb, vec(OC)=vecc , then vec(AB)+2vec(BC)+3vec(CA)=

If G is the centroid of Delta ABC and G' is the centroid of Delta A' B' C' " then " vec(A A)' + vec(B B)' + vec(C C)' =

If O is the circumcentre, G is the centroid and O' is orthocentre or triangle ABC then prove that: vec(OA) +vec(OB)+vec(OC)=vec(OO')

If O is the circumcentre and P the orthocentre of Delta ABC , prove that vec(OA)+ vec(OB) + vec(OC) =vec(OP) .

Statement 1: In DeltaA B C , vec (A B)+ vec (BC)+ vec (C A)=0 Statement 2: If vec (O A)= vec a , vec (O B)= vec b ,t h e n \ vec (A B)= vec a+ vec b

Let G be the centroid of Delta ABC , If vec(AB) = vec a , vec(AC) = vec b, then the vec(AG), in terms of vec a and vec b, is

Statement 1: In "Delta"A B C , vec A B+ vec A B+ vec C A=0 Statement 2: If vec O A= vec a , vec O B= vec b ,t h e n vec A B= vec a+ vec b