Tag: constructions

Questions Related to constructions

If $A=(1, 2, 3)$ and $B(3, 5, 7)$ and P, Q are the points on AB such that AP$=$PQ$\neq$QB, then the mid point of PQ is?

  1. $(2, 3, 5)$

  2. $\left(2, \dfrac{7}{2}, 5\right)$

  3. $(2, 4, 5)$

  4. $(4, 7, 0)$


Correct Option: A

The locus of the mid-point of a chord of the circle ${ x }^{ 2 }+{ y }^{ 2 }=4$ which subtends a right angle at the origin, is

  1. $x + y = 2$

  2. $x^2 + y^2 = 1$

  3. $x^2 + y^2 = 2$

  4. $x + y = 1$


Correct Option: A

The locus of the mid-point of that chord of parabola which subtends right angle on the vertex will be :

  1. $y^{ { 2 } }-2ax+4{ a }^{ 2 }=0$

  2. $y ^ { 2 } = a ( x - 4 a )$

  3. $y ^ { 2 } = 4 a ( x - 4 a )$

  4. $y^{ { 2 } }+3ax+4{ a }^{ 2 }=0$


Correct Option: A

The locus of the mid-point of that chord of parabola which subtends right angle on the vertex will be

  1. $y ^ { 2 } - 2 a x + 8 a ^ { 2 } = 0$

  2. $y ^ { 2 } = a ( x - 4 a )$

  3. $y ^ { 2 } = 4 a ( x - 4 a )$

  4. $y ^ { 2 } + 3 a x + 4 a ^ { 2 } = 0$


Correct Option: A

The locus of the middle points of chords of length $4$ on the circle $x^ {2}+y^ {2}=16$

  1. A straight line

  2. A circle of radius

  3. A circle of radius $2\sqrt {3}$

  4. An ellipse


Correct Option: A

If the coordinates of the mid-points of side $AB$ and $AC$ of $\triangle ABC$ are $D(3,5)$ and $E(-3,-3)$ respectively, the $BC=$

  1. $10$

  2. $15$

  3. $20$

  4. $30$


Correct Option: A

Find a point on the y-axis which equidistant from the points $A(6,5)$ and $B(-4,3)$

  1. $(0,9)$

  2. $(9,0)$

  3. $(3,0)$

  4. $(4,0)$


Correct Option: A

If $(-6,-4)$ and $(3,5)$ are the extremities of the diagonals of a parallelogram and $(-2,1)$ is its third vertex, then its fourth vertex is 

  1. $(-1,0)$

  2. $(0,-1)$

  3. $(-1,1)$

  4. none of these


Correct Option: A
Explanation:
Given,

$P(-6,-4),Q(3,5),R(-2,1),S(\alpha ,\beta )$

Let $P$ and $Q$ are the extremities of diagonals of a parallelogram, and 

$R$ and $S$ will be the extremities of diagonals of a parallelogram

Now,

midpoint of $PQ=\dfrac{3-6}{2},\dfrac{5-4}{2}=\dfrac{-3}{2},\dfrac{1}{2}$

midpoint of $RS\Rightarrow \dfrac{-2+\alpha }{2}=-\dfrac{3}{2}$

$\Rightarrow \alpha =-3+2=-1$

Now,

$\dfrac{\alpha +\beta }{2}=\dfrac{1}{2}$

$\Rightarrow \beta =0$

Therefore, coordinates of 4th vertex is $(-1,0)$

The mid point of the line joining the points  $\left( \log _ { 2 }  8 , \log _ { 4 }  16 \right)$  and  $\left( \sin 90 ^ { \circ } , \cos \theta \right)$  is

  1. $\sqrt { 2 }$

  2. $\sqrt { 3 }$

  3. $\sqrt { 5 }$

  4. $\sqrt { 7 }$


Correct Option: A

A (a,b) and (0,0) are two fixed points, ${ M } _{ 1 }$ is the mid points of AB, ${ M } _{ 2 }$ is the midpoint of $A{ M } _{ 1 },{ M } _{ 3 }$ is the midpoint of $A{ M } _{ 2 }$ and so on then ${ M } _{ 5 }$ =in

  1. $\left( \dfrac { 7a }{ 8 } ,\dfrac { 7b }{ 8 } \right) $

  2. $\left( \dfrac { 15a }{ 16 } ,\dfrac { 15b }{ 16 } \right) $

  3. $\left( \dfrac { 31a }{ 32 } ,\dfrac { 15b }{ 32 } \right) $

  4. $\left( \dfrac { 63a }{ 64 } ,\dfrac { 15b }{ 64 } \right) $


Correct Option: A