Answer:
The length of line segment AB = 3.4 cm.
Explanation:
Given:
The area of the regular octagon is approximately = 54 cm²
A regular octagon has an apothem with length = 4 cm
AB = side of the octagon
To Find:
AB = side of the octagon = ?
Solution:
A regular octagon has an Eight equal Side
We Know that,

substituting the given values in equation we get

Now,
Perimeter = 8 × Side
∴ Perimeter = 8 × AB
∴ 27 = 8 × AB
∴

After rounded to nearest 10th we get
AB =3.4 cm
The length of line segment AB = 3.4 cm.