Show that the points $ (1,1),(4,4) $ and $ (6,2) $ are the vertices of a right angled triangle.


Given:

Given points are \( (1,1),(4,4) \) and \( (6,2) \).

To do:

We have to prove that the points \( (1,1),(4,4) \) and \( (6,2) \) are the vertices of a right-angled triangle.

Solution:

Let the vertices of a \( \Delta \mathrm{ABC} \) are \( \mathrm{A}(1,1), \mathrm{B}(4,4) \) and \( \mathrm{C}(6,2) \).

We know that,

The distance between two points \( \mathrm{A}\left(x_{1}, y_{1}\right) \) and \( \mathrm{B}\left(x_{2}, y_{2}\right) \) is \( \sqrt{\left(x_{2}-x_{1}\right)^{2}+\left(y_{2}-y_{1}\right)^{2}} \).

Therefore,

\( \mathrm{AB}=\sqrt{\left(x_{2}-x_{1}\right)^{2}+\left(y_{2}-y_{1}\right)^{2}} \)

\( =\sqrt{(4-1)^{2}+(4-1)^{2}} \)

\( =\sqrt{(3)^{2}+(3)^{2}} \)

\( =\sqrt{9+9} \)

\( =\sqrt{18}=3\sqrt2 \)

Similarly,

\( \mathrm{BC}=\sqrt{(6-4)^{2}+(2-4)^{2}} \)

\( =\sqrt{(2)^{2}+(-2)^{2}} \)

\( =\sqrt{4+4}=2\sqrt{2} \)

\( \mathrm{CA}=\sqrt{(6-1)^{2}+(2-1)^{2}} \)

\( =\sqrt{(5)^{2}+(1)^{2}} \)

\( =\sqrt{25+1} \)

\( =\sqrt{26} \)

Here,

\( \mathrm{BC} \) is the longest side.

\( \mathrm{AB}^{2}+\mathrm{CA}^{2}=(\sqrt{18})^{2}+(\sqrt{8})^{2} \)

\( =18+8=26 \)

\( \mathrm{BC}^{2}=(\sqrt{26})^{2}=26 \)

\( \therefore \mathrm{AB}^{2}+\mathrm{CA}^{2}=\mathrm{BC}^{2} \)

Therefore, \( \Delta \mathrm{ABC} \) is a right triangle.

Hence proved.

Tutorialspoint
Tutorialspoint

Simply Easy Learning

Updated on: 10-Oct-2022

83 Views

Kickstart Your Career

Get certified by completing the course

Get Started
Advertisements