\(L:\) \(\frac{x+2}{4}=\frac{y−1}{2}=\frac{z+1}{3}\)
Let
\(P=(4t−2,2t+1,3t−1)\)
\(∵ P\) is the foot of perpendicular of \((1, 2, 4)\)
\(∴ 4(4t – 3) + 2(2t – 1) + 3(3t – 5) = 0\)
\(⇒29t=29⇒t=1\)
\(∴ P = (2, 3, 2)\)
Now, distance of \(P\) from the plane
\(3x + 4y + 12z + 23 = 0\), is
\(\begin{vmatrix}\frac{6+12+24+23}{\sqrt{9+16+144}}\end{vmatrix}=\frac{65}{13}=5\)
Two circular discs of radius \(10\) cm each are joined at their centres by a rod, as shown in the figure. The length of the rod is \(30\) cm and its mass is \(600\) g. The mass of each disc is also \(600\) g. If the applied torque between the two discs is \(43\times10^{-7}\) dyne·cm, then the angular acceleration of the system about the given axis \(AB\) is ________ rad s\(^{-2}\).

Method used for separation of mixture of products (B and C) obtained in the following reaction is: 
The length of the perpendicular drawn from the point to the line is the distance of a point from a line. The shortest difference between a point and a line is the distance between them. To move a point on the line it measures the minimum distance or length required.
The following steps can be used to calculate the distance between two points using the given coordinates:
Note: If the two points are in a 3D plane, we can use the 3D distance formula, d = √(m2 - m1)2 + (n2 - n1)2 + (o2 - o1)2.
Read More: Distance Formula