Please show step by step… i don’t understand!

Answer:
14.47 . . . units
Step-by-step explanation:
Given the vertices of triangle XYZ are (-1, 3), (3, 0) and (-1, -2), you want the perimeter rounded to hundredths.
The perimeter of a polygon is the sum of the lengths of the sides. When the points defining a side are on a vertical line, as with segment XZ, the length is the difference of y-coordinates.
When the points are not on a horizontal or vertical line, the distance between them can be found using the distance formula.
The distance between (x1, y1) and (x2, y2) is given by the formula ...
d = √((x2 -x1)² +(y2 -y1)²)
The length of segment XY is ...
d = √((3 -(-1))² +(0 -3)²) = √(4² +(-3)²) = √25 = 5
The length of segment YZ is ...
d = √((-1 -3)² +(-2-0)²) = √((-4)² +(-2)²) = √20 ≈ 4.47
Side XZ has length (3 -(-2)) = 5, the difference of y-coordinates. Then the perimeter is ...
P = XZ +XY +YZ = 5 +5 +4.47
P = 14.47 . . . . units
The perimeter of the triangle is about 14.47 units.