Question

find the number of sides of a regular polygon when each of its angles has measure of 160 degree

Answer 1

The formula for finding the internal angle of a regular polygon is
$\frac{(2n - 4) \times 90}{n}$
Its value is 160
Equating
$\frac{(2n - 4) \times 90}{n} = 160 \\ 180n - 360 = 160n \\ 20n = 360 \\ n = 18$
The polygon has 18 sides.
That's quite a number of sides isn't it?
I wonder what it would look like.