9514 1404 393
Answer:
15.8
Step-by-step explanation:
The distance formula is ...
d = √((x2 -x1)^2 +(y2 -y1)^2)
so the distance from A to B is ...
AB = √((-1-5)^2 +(1-(-1))^2) = √((-6)^2 +2^2) = √40 ≈ 6.3
Lengths BC and CA are similarly computed. (A spreadsheet does this nicely.)
The perimeter is the sum of the side lengths. It is ...
P = AB +BC +CA
P = 6.3 + 4.1 + 5.4
P = 15.8
The perimeter of ∆ABC is 15.8 units.
