Sagot :
Answer:
A simple (non-self-intersecting) quadrilateral is a parallelogram if and only if any one of the following statements is true: Two pairs of opposite sides are parallel (by definition). Two pairs of opposite sides are equal in length. Two pairs of opposite angles are equal in measure.
Area: b × h (base × height); ab sin θ (product of adjacent sides and sine of the vertex
Properties: convex
Step-by-step explanation:
By comparison, a quadrilateral with just one pair of parallel sides is a trapezoid in American English or a trapezium in British English.
The three-dimensional counterpart of a parallelogram is a parallelepiped.
The etymology (in Greek παραλληλ-όγραμμον, parallēl-ógrammon, a shape "of parallel lines") reflects the definition.
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