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8-1 Angles of Polygons. Vocab : diagonal. Theorem 8.1. Example 1. Theorem 8.2. Example 2. 8-2 Parallelograms. Vocab : parallelogram. Parallelogram. A parallelogram is a quadrilateral with both pairs of opposite sides parallel. Properties of parallelograms. Opposite sides are congruent
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8-1 Angles of Polygons Vocab: diagonal
8-2 Parallelograms Vocab: parallelogram
Parallelogram • A parallelogram is a quadrilateral with both pairs of opposite sides parallel.
Properties of parallelograms • Opposite sides are congruent • Opposite angles are congruent • Consecutive angles are supplementary • If it has one right angle, it has four right angles
Diagonals of Parallelograms • The diagonals of a parallelogram bisect eachother. • RQ = QT • UQ = QS
Diagonal separates congruent triangles • Each diagonal separates the parallelogram into two congruent triangles.
Proving Parallelograms • If both pairs of opposite sides are congruent, • If both pairs of opposite angles are congruent, • If the diagonals bisect each other, • If one pair of opposite sides is both parallel and congruent, • then the quadrilateral is a parallelogram.