Answer:
a. 25 units
Explanation:
The distance formula can be used to find the length of the given side.
d = √((x2 -x1)² +(y2 -y1)²) = √((3-(-1))² +(-1-2)²) = √(16+9) = √25 = 5
If each of the 5 sides has length 5 units, then the perimeter is ...
5 × (5 units) = 25 units