No it must have 3 or more interior angles
Only if it is a regular polygon.
Only if the polygon is "regular".
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.
Only when it is a regular polygon that all interior angles are of equal measure
If the polygon is regular, the measure of one interior angle of a 24 side polygon is 165 degrees.
I believe to what you are referring is a concave polygon. This is when one of the sides "falls into" the interior of the polygon, which can be tested by a line test. The other kind of polygon, where all sides are exterior, are called convex.
Anything you like. Any single interior angle of a polygon is indeterminate - the only constraint is on the sum of all the interior angles.
The angles between adjacent sides of a polygon that are interior to the polygon. If the polygon is convex, the interior angles are always less than 180 degrees. If it is concave, at least one interior angle will be greater than 180 degrees.
Only when the polygon is a regular convex polygon. Such as an equilateral triangle, or a square, or a regular pentagon.
Not too sure of the question but the only polygon that has no diagonals is a triangle.
A quadrilateral is the only polygon whose interior angles add up to 360 degrees.
If one interior angle is 165 degrees, find the number of sides of the polygon.