Question #eb26d

Question

1507 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-10-02T19:03:02

28.3

Find the distances between each point. (it's useful to draw a diagram here)
Let's call point (-9,-6) A,(-4,-5) B and (4,-9) C.

Length AB: $x$ component is $-9--4=-9+4=5$
$y$ component is $-6--5=1$
Now the length of the line is $sqrt(5^2+1^2) = sqrt26$ - using pythagoras.

Length BC:
$x$ component is 5+4 = 9
$y$ component is -5 to -9 = 4
Length = $sqrt(9^2 +4^2) = sqrt97$

Length CA:
$x$ component is 4+9 =13
$y$ component is -9 to -6 = 3
Length = $sqrt(13^2+3^2)=sqrt(178)$

Now add all the lengths together to find the perimeter:
$sqrt26+sqrt97+sqrt178$

decimal approximation = 28.3 units.