Well right here the answwer is 45°; 67.5° and let me explain why is it like this: There are 8 radials in the Octagon so the angle between 2 will be 360/8 = 45 Now have in mind that the Octagon is made up of 8 isoceles triangles. So If the vertex of the isoceles triangle is 45 then the angle opposite the two equal sides will be (180 -45) / 2 = 67.5 Hope this is clear and easy to understand
