Why would you need a "formula"
First of all, we should assume that it is a regular octogon
Then you would have 8 congruent and isosceles triangle
with a vertex angle of 45°
Depending on what information is given:
1. If you know one the isosceles sides, let's call it s
then area = 8(1/2)(s^2)sin45°
2. If you know the side of the octagon,
then it is easy to find the height of each triangle,
then use (1/2)(base)(height) to find the area of ONE triangle,
then multiply it by 8
What is the formula of Surface area of a Octagon?
1 answer
1 answer