A(-3, -1); B(2, -1), C(2, 3)
You can read the length of AB and BC.
|AB| = 5
|BC| = 4
Use the Pythagorean theorem:
[tex]|AC|^2=5^2+4^2\\\\|AC|^2=25+16\\\\|AC|^2=41\to|AC|=\sqrt{41}\\\\|AC|\approx6.4[/tex]
The perimeter:
[tex]P=|AB|+|BC|+|AC|\\\\P=5+4+6.4=15.4[/tex]
