Do all trapezoids and parallelograms have only one set of parallel lines? Explain your answer.

We can put squares in the intersection of the two circles. From this diagram, you can see that a square is a quadrilateral, a parallelogram, a rectangle, and a rhombus! Is a trapezoid a parallelogram? No, because a trapezoid has only one pair of parallel sides.

Step-by-step explanation:

δabc ≅ δdcb by sas because

db ≅ ac . . given (side)

bc ≅ bc . . reflexive property (side)

∠dbc ≅ ∠ acb . . alternate interior angles where transversal bc crosses parallel lines bd and ac (included angle)