Coordinate Geometry Question 28

Question: The points (3a, 0), (0, 3b) and (a, 2b) are

[MP PET 1982]

Options:

A) Vertices of an equilateral triangle

B) Vertices of an isosceles triangle

C) Vertices of a right angled isosceles triangle

D) Collinear

Show Answer

Answer:

Correct Answer: D

Solution:

$ l_1=\sqrt{{{(3a)}^{2}}+{{(3b)}^{2}}}=3\sqrt{a^{2}+b^{2}} $

$ l_2=\sqrt{a^{2}+b^{2}}=\sqrt{a^{2}+b^{2}} $

$ l_3=\sqrt{{{(2a)}^{2}}+{{(2b)}^{2}}}=2\sqrt{a^{2}+b^{2}} $
$ \Rightarrow l_1=l_2+l_3 $

Hence the points are collinear.