You are a regular five sided pentagon.
15 equal sides
The sum of the interior angles of any regular polygon of n sides is equal to 180(n - 2) degrees. 1980 degrees.
Only when it is a regular polygon that all interior angles are of equal measure
It has 18 sides (an octadecagon) because the number of identical angles on the polygon must always equal 360 degrees.
a "regular" polygon
A polygon with interior angles that sum to 900 degrees is a nonagon, which has 9 sides. The formula for the sum of interior angles of a polygon is given by ( (n - 2) \times 180 ) degrees, where ( n ) is the number of sides. Setting this equal to 900 degrees, we find ( n = 9 ). Therefore, a polygon with a sum of interior angles of 900 degrees is a nonagon.
Only if the polygon is "regular".
All of the angles are equal in a "regular" polygon. (All of the sides are too.)
If all of the interior angles of the polygon add up to 180 degrees, then the polygon is a triangle.
True, an equilateral triangle has three equal interior angles of 60 degrees.
The sum of the exterior angles of a polygon is equal to 360 degrees.
If the 12-sided polygon is 'regular', then each of its exterior angles is 30 degrees. Whether the polygon is regular or not, all 12 of its exterior angles still add up to 360 degrees, but they may not all be equal.