A triangle having all angles less than 90 degrees is a polygon having no parallel sides and all acute angles.
parallelogram
A rhombus (pushed over square) will give you 2 pairs of parallel, congruent sides, 2 acute angles and 2 obtuse angles.
triangle
It is a parallelogram.
A rhombus - or parallelogram.
A polygon with 4 or more sides can meet these requirements.
A parallelogram is a quadrilateral with opposite sides parallel and congruent.
A right trapezoid is a four-sided polygon with two right angles and two parallel sides.
A parallelogram has 2 pairs of parallel sides.
Trapezium!
parallelogram
A trapezoid