Question

How do you find the perimeter of a triangle given (2, 2), (-2, 2), and (-2, -3)?

Answer 1

Perimeter is `15.4`

Explanation:

To find perimeter, we should find sum of all the three sides of the triangle formed by `A(2,2)`, `B(-2,2)` and `C(-2,-3)`

Before we do that observe that between `A` and `B`, ordinate is same and hence line joining them is parallel to `x`-axis. Further as difference between abscissa is `4`, length of `AB` is `4`.

Also observe that between `B` and `C`, abscissa is same and hence line joining them is parallel to `y`-axis. Further as difference between ordinate is `5`, length of `BC` is `5`.

As `AB` is parallel to `x`-axis and `BC` is parallel to `y`-axis, `DeltaABC` is right angled triangle and hence from Pythagoras theorem, hypotenuse `AC=sqrt(4^2+5^2)=sqrt(16+25)=sqrt41=6.403~=6.4`

and perimeter is `4+5+6.4=15.4`