+33661 Consider the octagon to be made up of 8 triangles each of which look like the image below:
Angle β is (180-45)/2 = 67.5°
Use the sin rule to get s
s/sin(45°) = 1.4/sin(67.5°)
$${\mathtt{s}} = {\frac{{\mathtt{1.4}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}{\left({\mathtt{45}}^\circ\right)}}{\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}{\left({\mathtt{67.5}}^\circ\right)}}} \Rightarrow {\mathtt{s}} = {\mathtt{1.071\: \!513\: \!610\: \!623\: \!269\: \!6}}$$
s ≈ 1.07m
+33661 Consider the octagon to be made up of 8 triangles each of which look like the image below:
Angle β is (180-45)/2 = 67.5°
Use the sin rule to get s
s/sin(45°) = 1.4/sin(67.5°)
$${\mathtt{s}} = {\frac{{\mathtt{1.4}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}{\left({\mathtt{45}}^\circ\right)}}{\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}{\left({\mathtt{67.5}}^\circ\right)}}} \Rightarrow {\mathtt{s}} = {\mathtt{1.071\: \!513\: \!610\: \!623\: \!269\: \!6}}$$
s ≈ 1.07m
