5) 72
6) 60
7) 140
8) 175
Step-by-step explanation
Let's remember the interior and exterior angle add up to 180°
so
then
Step 1
5)
let
interior angle= 108
replace
hence
5) 72
Step 2
6)
let
interior angle= 120
replace
hence
6) 60
Step 3
7) 40
let
interior angle= 40
replace
hence
7) 140
Step 4
finally,
8)5
let
interior angle= 5
replace
hence
8) 175
I hope this helps you