It is a right angle triangle
There is only one regular polygon which contains right angles - this is a square. None of the other regular polygons from 3 sides and upwards has a right angle.
A right scalene triangle.
Providing that it is a regular polygon it will have 8 sides.
a right triangle
If the only information that you have is the angle and the shape is a polygon, then you cannot determine how many sides the polygon consists of. The minimum number of sides is 3, but without seeing a picture, or knowing what type of polygon (e.g. right triangle or equalaterial triangle), then you won't be able to determine how many sides the polygon has.
2
It will have 360/120 = 3 sides
well if its 120 degrees it must have 3 sides
It is the right angle triangle which has 3 sides whereas all quadrilaterals have 4 sides.
The minimum number of sides for a polygon is 3 sides.
The longest side is always opposite the right angle so the sides of the right angle are 3 and 4 units.