The central angle is
The SAS formula for the area of a triangle is
"The area of a triangle is equal to one-half the product of
two sides multipled by the sine of the included angle.
Area of the triangle =
and as we see below:
the regular octagon is composed of 8 such triangles,
all congruent. Therefore:
The area of the regular octagon = .
That's approximately 282.8427125 square units.
Edwin
