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Three Dimensional Geometry

Question
CBSEENMA12035859

Find the equation of the plane passing through the points (3, 4, 1) and (0, 1, 0) and parallel to the line x + 32 = y - 37 = z - 25

Solution

Equation of the plane passing through the point (3, 4, 1) is:

 

a ( x - 3 ) + b ( y - 4 ) c ( z - 1 ) = 0        .............(1)

 

Where a, b, c are the direction ratios of the normal to the plane 

It is given that the plane (1) passes through the point 9 0, 1, 0 ).

 a - 3 + b - 3 + c - 1 = 0

3a + 3b + c = 0                                  ...............(2)

It is also given that the plane (1) is parallel to the line 

 

x + 32 = y - 37 = z - 25.

 

So, this line is perpendicular to the normal of the plane (1).

 2a + 7b + 5c = 0                                 ................(3)

Solving equations (2) and (3), we have:

a3 x5 - 7 x 1 = b1 x 2 - 5 x 3 = c3 x 7 - 2 x 3 a8 = b-13 = c15

So, the direction ratios of the normal to the required plane are multiples of 8, -13, 15.

Therefore, equation (1) becomes:

8 ( x - 3 ) -13 ( y - 4 ) + 15 ( z - 1) = 0

 8x - 13y + 15z + 13 = 0.

Which is the required equation of the plane.