Question:

The volume of the tetrahedron with vertices P (-1, 2, 0), Q ( 2, 1, -3), R (1, 0, 1) and S (3, -2, 3) is

Updated On: Apr 19, 2024
  • $\frac{1}{3}$
  • $\frac{2}{3}$
  • $\frac{1}{4}$
  • $\frac{3}{4}$
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is B

Solution and Explanation

Given : The vertices of tetrahedron are
P(-1, 2, 0), Q(2, 1, -3), R(1, 0, 1) & S(3, -2, 3)
$\therefore$ Volume of tetrahedron $= \ \frac{1}{6} \ [\vec{PQ} \ \vec{PR} \ \vec{PS}]$
Now,
$\vec{PQ}=(2+1)\hat{i}+(1-2)\hat{j}+(-3)\hat{k}=3\hat{i}-\hat{j}-3\hat{k}$
Similarly, $\vec{PR}=2\hat{i}-2\hat{j}+\hat{k}$
$\& \ \ \ \ \ \vec{PS}=4\hat{i}-4\hat{j}+3\hat{k}$
$\therefore $ Volume of tetrahedron

$=\frac{1}{6} \begin{vmatrix}
3 & -1 & -3\\
2 & -2 & 1 \\
4 & -4 & 3 \end{vmatrix} =\frac{2}{3}$
Was this answer helpful?
0
0

Concepts Used:

Plane

A  surface comprising all the straight lines that join any two points lying on it is called a plane in geometry. A plane is defined through any of the following uniquely:

  • Using three non-collinear points
  • Using a point and a line not on that line
  • Using two distinct intersecting lines
  • Using two separate parallel lines

Properties of a Plane:

  • In a three-dimensional space, if there are two different planes than they are either parallel to each other or intersecting in a line.
  • A line could be parallel to a plane, intersects the plane at a single point or is existing in the plane.
  • If there are two different lines that are perpendicular to the same plane then they must be parallel to each other.
  • If there are two separate planes which are perpendicular to the same line then they must be parallel to each other.