To indicate that a pair of lines are parallel you mark them both with an arrow. If there is another pair of parallel lines on the same shape you mark those with a double arrow.
A regular pentagon has no parallel lines, but you can create an irregular pentagon with one pair of parallel lines if you make a traditional 'house' shape with parallel 'walls'.
A trapezoid has 4 sides, 2 acute and 2 obtuse angles, and only one pair of parallel sides
Only one pair: trapezium.
None.
A parallelogram has 1 pair of parallel lines that is also regular. See the related link.
A trapezium (has only one pair of unequal parallel lines).
Not sure about angels and parrellel, but a trapezium has four angles and only one pair of parallel lines.
To indicate that a pair of lines are parallel you mark them both with an arrow. If there is another pair of parallel lines on the same shape you mark those with a double arrow.
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.
If you mean one pair of parallel lines, then you're talking about a trapezoid.
An isosceles trapezoid would seem to fit the given description.
A Trapezium is a four sided shape with only one pair of parallel lines.
At least one pair, or one pair? If it is one pair, then it depends if the shape is regular or irregular.
Trapizium
No, one pair.
trapezoid