Determine the sum of angles of octagon.
[tex]\begin{gathered} S=(n-2)\times180 \\ =(8-2)\times180 \\ =6\cdot180 \\ =1080 \end{gathered}[/tex]Let measure of each angle of six congurent angle be x.
Then measure of each of other two remaining angle is (x + 20).
Determine the value of x by using the sum of angles of octagon.
[tex]\begin{gathered} x+x+x+x+x+x+x+20+x+20=1080 \\ 8x=1080-40 \\ x=\frac{1040}{8} \\ =130 \end{gathered}[/tex]So measure of each angle of six congurent angle is 130 degree.
Determine the measure of two remaining angles.
[tex]\begin{gathered} x+20=130+20 \\ =150 \end{gathered}[/tex]Thus measure of angles of octagone are,
Six angle measure 130 degree each and two angle measure 150 degree each.
[tex]130,130,130,130,130,130,150,150[/tex]