A 4 sided shape
a square
irregular square or rectangle
A shape with no right angles and one pair of parallel lines would be called a trapezoid in the USA, and a trapezium in Britain.
trapezoid
A pair of infinitely long parallel lines.
A trapezoid
A right-angle triangle.
A 3-sided shape with 1 pair of perpendicular lines is called a right triangle. In a right triangle, one of the angles is a right angle, which means it measures 90 degrees. The side opposite the right angle is called the hypotenuse, while the other two sides are called the legs. The perpendicular lines in a right triangle are formed by the legs meeting at a right angle.
A Trapezium is a four sided shape with only one pair of parallel lines.
A 4 sided shape
A three-sided shape with one pair of perpendicular lines is called a right triangle. In a right triangle, one angle is a right angle (90 degrees), which means that one pair of sides are perpendicular to each other. The other two angles are acute, measuring less than 90 degrees. The Pythagorean theorem can be used to find the lengths of the sides of a right triangle.
At least one pair, or one pair? If it is one pair, then it depends if the shape is regular or irregular.
A trapezoid is a four-sided figure (or "quadrilateral") with only one pair of parallel sides.
a square
Trapezoid
irregular square or rectangle