What kind of angles does a trapezoid have?

In its most general form, a trapezoid (or trapezium, outside of North America) is a four-sided figure with exactly one pair of parallel sides. The two parallel sides do not have to be the same length; therefore a trapezoid will have either:

1. Two acute angles (less than 90º) and two obtuse angles (greater than 90º) OR
2. Two right angles, one acute angle, and one obtuse angle.

Case (2) is a special type of Case (1).