Answer:
20.8mm
Step-by-step explanation:
We know that an octagon has 8 sides, and since this is a regular octagon we can safely say that all sides are equal.
This means all sides are 2.6mm.
So if we run the calculation:
2.6mm × 8 = 20.8mm (Side Length × Number of Sides = Perimeter)
We have our final answer!
