Question

Differences between the external angle and n-1 sides regular polygon and n+2 side regular polygon is 6 degree then what is the each external angle

Answer 1

If you know the rule between exterior angle θ and the number of sides, n:
θ=360/n
then
360/(n-1)-360/(n+2)=6
Solve for n, then calculate θ for each polygon.
(answer is between 10 and 15, reject negative root)