It doesn't need any in order to be a trapezoid. It can have a max of two pairs of perpendicular sides.
None but it has end sides of equal lengths
Yes, an isosceles trapezoid is one example.
Any polygon can have only 1 pair of perpendicular sides.
To calculate the area of a trapezoid, you have to know the lengths of three sides because 1/2*(sum of parallel sides)*perpendicular height = area
A right trapezoid has exactly one pair of perpendicular lines and is a quadrilateral.
trapezoid rhombus parellogrm