Answer: 28.84 units
Step-by-step explanation:
Let's use the distance formula to find the distance from A to B (aka the length of side AB).
Side AB is roughly 3.6056 units long.
In any regular polygon, the sides are the same length.
Because of that, this regular octagon has 8 sides of roughly 3.6056 units each.
The perimeter is 8*3.6056 = 28.8448 approximately. This rounds to 28.84 when rounding to the nearest hundredth (aka 2 decimal places).