A regular polygon requires all sides to be the same length; in a rectangle not all four sides are the same length (they form two pairs of sides of equal length) and so it is not a regular polygon.
rectangle
A square is a four-sided polygon with two congruent parallel sides.
A polygon.
A kite is a four-sided polygon with two pairs of congruent adjacent sides.
An isosceles trapezoid has 2 sides that are the same length.
A regular polygon requires all sides to be the same length; in a rectangle not all four sides are the same length (they form two pairs of sides of equal length) and so it is not a regular polygon.
rectangle
A square is a four-sided polygon with two congruent parallel sides.
A polygon.
A right trapezoid is a four-sided polygon with two right angles and two parallel sides.
A kite is a four-sided polygon with two pairs of congruent adjacent sides.
A polygon with three vertices and three sides is a triangle. A polygon with four vertices and four sides is a quadrilateral.
a prism
That would have to be a trapezoid
A polygon with two equal sides!
A three-sided polygon is called a triangle. If two of the sides are of the same length, it is said to be an isosceles triangle.