Distance formula lang yan.

d =  \sqrt{(x_{2} -  x_{1})^2 + (y_{2} -  y_{1})^2}

Let A(2,3) B(5,7) C(-3,4) be the corresponding vertices

1)get the distance of AB, AC, and BC.

AB= \sqrt{(5 - 2)^2 + (7 - 3)^2}
AB = 5
do the same for AC and BC.

2)since you're supposed to find the perimeter just add the values you've obtained

Answer for number one is approximately 18.64

If you feel really lazy, just look up distance formula calculators on google=))