# Solution of missingVertex Question1

In this page solution of missingvertex question1 we are going to see he detailed solution of the first question.

Question 1 :

Find the missing vertex of triangle whose two vertices are (-3,-9) (-1,6) and its centroid is (-1/3 , 2 )

Solution:

Centroid of a triangle = (x₁+x₂+x₃)/3, (y₁+y₂+y₃)/3

let A,B and C be the vertices of triangle ABC. Here A (-3, -9), B (-1,6) and let us take the third missing vertex be (a,b).

x₁ = -3          x₂ = -1          x₃ = a

y₁ = -9          y₂ = 6           y₃ = b

(-1/3 , 2) =  [(-3) + (-1) + a ]/3 , [ (-9) + 6 + b ]/3

(-1/3 , 2) =  [-3 - 1 + a ]/3 , [ -9 + 6 + b ]/3

(-1/3 , 2) =  [-4 + a ]/3 , [ -3 + b ]/3

Equating x and y coordinates

[-4 + a ]/3 = - 1/3              [ -3 + b ]/3  = 2

- 4 + a = -1                          - 3 + b = 2 x 3

a = -1 + 4                   -3 + b = 6

a = 3                                 b = 6 + 3

a = 3                                  b = 9

Therefore the third vertex is (3,9).

Question 2 :

Find the missing vertex of triangle whose two vertices are (-3,-9) (5,-8) and its centroid is (5/3 , -8/3 )

 (A) (1 , -2) (B) (3 , 9) (C) (1 , -5)

Question 3 :

Find the missing vertex of triangle whose two vertices are (4,5) (4,2) and its centroid is (2 , 3 )

 (A) (-2 , 2) (B) (3 , 6) (C) (1 , 2)

Question 4 :

Find the missing vertex of triangle whose two vertices are (3,1) (2,2) and its centroid is (7/3 , 1 )

 (A) (-2 , 1) (B) (2 , 6) (C) (2 , 0)

Question 5 :

Find the missing vertex of triangle whose two vertices are (3,1) (0,4) and its centroid is (0 , 2 )

 (A) (-2 , 0) (B) (-3 , 1) (C) (-1 , 2)

Question 6 :

Find the missing vertex of triangle whose two vertices are (1,10) (-7,2) and its centroid is (-3 , 19/3 )

 (A) (-3 , 7) (B) (3 , 1) (C) (1 , 0)

Question 7 :

Find the missing vertex of triangle whose two vertices are (-1,-3) (2,1) and its centroid is (1 , -2 )

 (A) (-3 , 4) (B) (2 , -4) (C) (1 , 4)

Question 8 :

Find the missing vertex of triangle whose two vertices are (1,1) (2,3) and its centroid is (-1/3 , 2 )

 (A) (-1 , 2) (B) (2 , 2) (C) (-2 , 2)