prove that the perpendicular drawn from the point (4,1) on the join of (2,-1) and (6,5) divides it in the ratio 5:8.

https://s3mn.mnimgs.com/img/shared/discuss_editlive/3021597/2012_07_25_12_52_35/2695545.png

let the required ratio be k : 1

Now, coordinates of point D = https://s3mn.mnimgs.com/img/shared/discuss_editlive/3021597/2012_07_25_12_52_35/mathmlequation4871036632538084014.png

Slope of line AD,

https://s3mn.mnimgs.com/img/shared/discuss_editlive/3021597/2012_07_25_12_52_35/mathmlequation8969987849439291072.png

https://s3mn.mnimgs.com/img/shared/discuss_editlive/3021597/2012_07_25_12_52_35/mathmlequation901483022287782723.png

Slope of line BC,

https://s3mn.mnimgs.com/img/shared/discuss_editlive/3021597/2012_07_25_12_52_35/mathmlequation9010003213453233516.png

Now,

https://s3mn.mnimgs.com/img/shared/discuss_editlive/3021597/2012_07_25_12_52_35/mathmlequation48543387693743623.png

Thus, required ratio = https://s3mn.mnimgs.com/img/shared/discuss_editlive/3021597/2012_07_25_12_52_35/mathmlequation4490018814206063741.png : 1 = 5 : 8

Hence, perpendicular drawn from the point (4, 1) on the line joining (6, 5) and (2, –1) divides it in the ratio 5 : 8 internally.

 

  • 32

first of all find the equation of the line having the points 2,-1 and 6,5. then find the perpendicular distance between the given external points and the equation finded then, find the perpendicular point on the line then after doing so use section formula to prove the given ratio.

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