3D Geometry Questions (578)

Let $(\alpha,\beta,\gamma)$ be the image of the point $(8,5,7)$ in the line $\dfrac{x-1}{2}=\dfrac{y+1}{3}=\dfrac{z-2}{5}$. Then $\alpha+\beta+\gamma$ is equal to:
The shortest distance between the lines $\dfrac{x-3}{2}=\dfrac{y+15}{-7}=\dfrac{z-9}{5}$ and $\dfrac{x+1}{2}=\dfrac{y-1}{1}=\dfrac{z-9}{-3}$ is:
The square of the distance of the image of the point $(6,1,5)$ in the line $\dfrac{x-1}{3}=\dfrac{y}{2}=\dfrac{z-2}{4}$, from the origin is _____
If the shortest distance between the lines $L_1:\vec{r}=(2+\lambda)\hat{i}+(1-3\lambda)\hat{j}+(3+4\lambda)\hat{k}$, $\lambda\in\mathbb{R}$ and $L_2:\vec{r}=2(1+\mu)\hat{i}+3(1+\mu)\hat{j}+(5+\mu)\hat{k}$, $\mu\in\mathbb{R}$ is $\dfrac{m}{\sqrt{n}}$, where $\gcd(m,n)=1$, then the value of $m+n$ equals:
Let $P(\alpha,\beta,\gamma)$ be the image of the point $Q(3,-3,1)$ in the line $\dfrac{x-0}{1}=\dfrac{y-3}{1}=\dfrac{z-1}{-1}$ and $R$ be the point $(2,5,-1)$. If the area of triangle $PQR$ is $\lambda$ and $\lambda^2=14K$, then $K$ is equal to:
Let the position vectors of the vertices $A$, $B$ and $C$ of a triangle be $2\hat{i}+2\hat{j}+\hat{k}$, $\hat{i}+2\hat{j}+2\hat{k}$ and $2\hat{i}+\hat{j}+2\hat{k}$ respectively. Let $l_1,l_2$ and $l_3$ be the lengths of perpendiculars drawn from the orthocentre of the triangle on the sides $AB$, $BC$ and $CA$ respectively, then $l_1^2+l_2^2+l_3^2$ equals:
A point P moves in the space such that \(3PA = 2PB\), then the locus of P is
Given lines can be written in vector forms as \(\vec{r} = (2\hat{i} + 3\hat{j} + 4\hat{k}) + \lambda(\hat{i} + \hat{j} - k\hat{k})\) and \(\vec{l} = (\hat{i} + 4\hat{j} + 5\hat{k}) + u(k\hat{i} + 2\hat{j} + \hat{k})\). The two lines will be coplanar if:
Let \(P(3, 2, 6)\) be a point in space and \(Q\) be a point on the line \(\vec{r} = (\hat{i} - \hat{j} + 2\hat{k}) + \mu(-3\hat{i} + \hat{j} + 5\hat{k})\). Then the value of \(\mu\) for which the vector \(\overrightarrow{PQ}\) is parallel to the plane \(x - 4y + 3z = 1\) is
Given \(\vec{r} \cdot (\hat{i} + 2\hat{j} + 2\hat{k}) = 15\) (a plane) and \(|\vec{r} - (\hat{j} + 2\hat{k})| = 4\) (a sphere with centre \((0,1,2)\) and radius 4). The centre of the circle formed by their intersection is:
Given a tetrahedron has vertices P(1, 2, 1), Q(2, 1, 3), R(−1, 1, 2) and O(0, 0, 0). The angle between the faces OPQ and PQR is:
The plane passing through the point (4, –1, 2) and parallel to the lines \(\dfrac{x+2}{3} = \dfrac{y-2}{-1} = \dfrac{z+1}{2}\) and \(\dfrac{x-2}{1} = \dfrac{y-3}{2} = \dfrac{z-4}{3}\) also passes through the point:
If $\vec{a}=\hat{i}+2\hat{j}+3\hat{k}$, $\vec{b}=2\hat{i}+7\hat{j}+2\hat{k}$, $\vec{x}\cdot\vec{a}=0$ and $\vec{x}\cdot\vec{c}=0$ for some non-zero vector $\vec{x}$, then value of $\vec{a}\cdot(\vec{b}\times\vec{c})$ is
The image of the line \(\dfrac{x-1}{3} = \dfrac{y-3}{1} = \dfrac{z-4}{-5}\) in the plane \(2x - y + z + 3 = 0\) is the line
The minimum value of $x^2+y^2+z^2$ if $ax+by+cz=p$ is
Line $\frac{x}{1}=\frac{6-y}{2}=\frac{z+8}{5}$ meets $\frac{x-5}{4}=\frac{y-7}{3}=\frac{z+2}{1}$ at $A$ and $\frac{x+3}{6}=\frac{3-y}{3}=\frac{z-6}{1}$ at $B$. Distance of midpoint of $AB$ from $2x-2y+z=14$ is
Let the direction ratios (DRs) of a line be \(\cos\left(\dfrac{\pi}{4}\right),\; \cos\left(\dfrac{\pi}{4}\right),\; \cos\theta\). The angle the line makes with the positive direction of z-axis is:
Given the planes x + 2y − 3z + 5 = 0 and 2x + y + 3z + 1 = 0. If a point P is (2, −1, 2), then
A line in the 3-dimensional space makes an angle \(\theta\,(0
Given lines \(\dfrac{x}{2} = \dfrac{y}{2} = \dfrac{z}{1}\) and \(\dfrac{x-5}{2} = \dfrac{y-2}{p/7} = \dfrac{z-3}{4}\). The value of \(p\) such that the angle between both lines satisfies \(\cos^{-1}\left(\dfrac{2}{3}\right)\) is:
Let \(P \equiv (3, 4, a)\) and \(Q \equiv (3, 4, \lambda + a)\) be two points. The area of triangle \(OPQ\) (where \(O\) is the origin) is \(\frac{5}{4}[(a+1)^2 + 5]\). If the least area is \(\frac{p}{q}\) (in lowest terms), find \(p + q\).
The plane containing the line \(\dfrac{x-3}{2} = \dfrac{y+2}{-1} = \dfrac{z-1}{3}\) and also containing its projection on the plane \(2x + 3y - z = 5\), contains which one of the following points?
The equation of the reflected ray is the line joining Q(6, 5, -2) and B(-10, -15, -14). Express this in standard form.
For what value of $a$ do three planes $x + y + z = 1$, $x + 2ay + z = 1$, and $ax^2 + y + z = 1$ intersect in a line?
182. In a tetrahedron \(OABC\), if \(\vec{OA} = \vec{i}\), \(\vec{OB} = \vec{i} + \vec{j}\) and \(\vec{OC} = \vec{i} + 2\vec{j} + \vec{k}\), if shortest distance between edges \(OA\) and \(BC\) is \(m\), then \(2m\) is equal to \(\ldots\) (Where \(O\) is the origin)
Ex. 46 Two lines whose equations are \(\frac{x}{-2} = \frac{y}{-3} = \frac{z}{-2}\) and \(\frac{x-3}{2} = \frac{y-2}{3} = \frac{z-1}{\lambda}\) lie in the same plane.The value of \(\sin^{-1} \sin \lambda\) is equal to
A line with direction cosines proportional to 2, 1, 2 meets each of the lines \(x = y + a = z\) and \(x + a = 2y = 2z\). The co-ordinates of each point of intersection are given by
Two spheres \(x^2 + y^2 + z^2 + 7x - 2y - z - 13 = 0\) and \(x^2 + y^2 + z^2 - 3x + 3y + 4z - 8 = 0\) intersect. The plane of intersection is: