NCERT Solutions
Class 11 - Mathematics - Chapter 11: INTRODUCTION TO THREE DIMENSIONAL GEOMETRY
EXERCISE 11.2

Question. 1

Find the distance between the following pairs of points:

(i) \((2, 3, 5)\) and \((4, 3, 1)\)

(ii) \((-3, 7, 2)\) and \((2, 4, -1)\)

(iii) \((-1, 3, -4)\) and \((1, -3, 4)\)

(iv) \((2, -1, 3)\) and \((-2, 1, 3)\)

Answer:

(i) \(2\sqrt{5}\)

(ii) \(\sqrt{43}\)

(iii) \(2\sqrt{26}\)

(iv) \(2\sqrt{5}\)

Question. 2

Show that the points \((-2, 3, 5)\), \((1, 2, 3)\) and \((7, 0, -1)\) are collinear.

Question. 3

Verify the following:

(i) \((0, 7, -10), (1, 6, -6)\) and \((4, 9, -6)\) are the vertices of an isosceles triangle.

(ii) \((0, 7, 10), (-1, 6, 6)\) and \((-4, 9, 6)\) are the vertices of a right angled triangle.

(iii) \((-1, 2, 1), (1, -2, 5), (4, -7, 8)\) and \((2, -3, 4)\) are the vertices of a parallelogram.

Question. 4

Find the equation of the set of points which are equidistant from the points \((1, 2, 3)\) and \((3, 2, -1)\).

Answer:

\(x - 2z = 0\)

Question. 5

Find the equation of the set of points \(P\), the sum of whose distances from \(A(4, 0, 0)\) and \(B(-4, 0, 0)\) is equal to 10.

Answer:

\(9x^2 + 25y^2 + 25z^2 - 225 = 0\)

NCERT Solutions Class 11 – Mathematics – Chapter 11: INTRODUCTION TO THREE DIMENSIONAL GEOMETRY – EXERCISE 11.2 | Detailed Answers