trapezoid
A trapezoid would fit the given description
Hexagon
A four-sided shape with one right angle is a quadrilateral. There is no more specific term, unless it has more than one right angle or has equal sides.
No shape has only 1 parallel side. A trapezoid is a 4-sided shape, or quadrilateral, with only 2 parallel sides; it does not necessarily have to have 2 right angles. (In the UK a trapezoid is called a trapezium.) In North America, a trapezium is a quadrilateral with 0 (no) parallel sides.
Square
a 3 sided shape is a right angle triangle
A trapezoid would fit the given description
Hexagon
octogan
A four-sided shape with one right angle is a quadrilateral. There is no more specific term, unless it has more than one right angle or has equal sides.
polygon
No shape has only 1 parallel side. A trapezoid is a 4-sided shape, or quadrilateral, with only 2 parallel sides; it does not necessarily have to have 2 right angles. (In the UK a trapezoid is called a trapezium.) In North America, a trapezium is a quadrilateral with 0 (no) parallel sides.
A right angled pentagon.
A 25-sided shape would have no parallel sides !
The shape can only be a rectangle! A rectangle is a four-sided 2-dimentional figure, where every angle is a right angle, opposite sides are parallel, but the 4 sides are NOT equal.
Square
An irregular pentagon.