A regular octagon has all its eight sides congruent. The line segments joining each of the vertices of a regular octagon to its center are called the radii of the octagon. These 8 radii divide a regular octagon into 8 congruent isosceles triangles. Area of each isosceles triangle is
,
where a is length of the side of the octagon and is the angle between two radii of the octagon.
In regular octagon
.
Then the area of regular octagon is
sq. m.
Answer: sq. m.