Number of sides of a regular polygon having each internal angle equal to 168 degree is 30.
Solution:
Given that interior angle of regular polygon = 168 degree
Need to determine number of sides of a regular polygon.
Let’s first calculate exterior angle of a regular polygon.
Exterior angle = 180 – interior angle = 180 – 168 = 12 degree

So number of sides of regular polygon having exterior angle of 12 degree is given as:

Hence number of sides of a regular polygon having each internal angle equal to 168 degree is 30