There is a formula which can help.
The sum of the interior angles of a polygon is 2n - 4 right angles.
When n = 12 then the interior angles total (2 x 12) - 4 = 24 - 4 = 20 right angles.
Then for a regular polygon, each angle measures (20 x 90) / 12 = 150°.
When the polygon is a regular polygon then it is perhaps quicker to calculate the external angle from which the interior angle can then be determined.
Exterior angle = 360 /12 = 30°
Interior angle = 180 - 30 = 150°
Each interior angle will measure 162 degrees
A regular polygon with each interior angle measuring 120 degrees is a hexagon.
If the polygon is regular, the measure of one interior angle of a 24 side polygon is 165 degrees.
It is: 180-exterior angle = interior angle because there are 180 degrees on a straight line
The only regular polygon with an interior angle of 90 degrees is the square, which has four sides. Other polygons can have an interior angle of 90 degrees, but they would not be regular polygons.
A regular polygon having an interior angle measure of 168o has 30 sides and is called a triacontagon.
The measure of each interior angle of a fifteen sided regular polygon, a pendedecagon, is 156o.
If the measure of an interior angle of a regular polygon is 140o, the polygon is a nonagon (sometimes called an ennagon) having 9 sides.
The interior angle of an octdecagon, an 18 sided regular polygon, is 160o.
Each interior angle will measure 162 degrees
A regular polygon with each interior angle measuring 120 degrees is a hexagon.
A regular polygon with 4 sides is a square. The measure of any interior angle of a square is 90 degrees.
Providing that it is a regular polygon then each interior angle will measure 160 degrees
If the polygon is regular, the measure of one interior angle of a 24 side polygon is 165 degrees.
A regular hexagon.
A pentagon (five sided regular polygon) has interior angles of 108°.
How many sides does a regular polygon have if the measure of each interior angle is equal to 172 degress ?