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Verifying properties of quadrilaterals. Recall the following important geometric formulas:. Proving Properties:. 1) To prove that two lines are parallel, their slopes must be equal. 2) To prove that two lines are perpendicular, their slopes must be negative reciprocals. Proving Properties:.
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Proving Properties: • 1) To prove that two lines are parallel, • their slopes must be equal. • 2) To prove that two lines are perpendicular, • their slopes must be negative reciprocals.
Proving Properties: • 3) To prove that side lengths are equal, • use the distance formula to calculate the distance between two points • 4) To prove that two lines bisect each other, • find their midpoints and they should be the same.
Types of Quadrilaterals • TRAPEZOID • 2 sides are parallel and the others are not • Prove using the slope formula
Types of Quadrilaterals • PARALLELOGRAM • 2 pairs of parallel sides • Prove using the slope formula
Types of Quadrilaterals • RECTANGLE • 4 right angles • Prove using the slope formula
Types of Quadrilaterals • SQUARE • 4 right angles • 4 equal side lengths • Prove using the slope and distance formulas
Types of Quadrilaterals • RHOMBUS • 4 sides equal • Prove using the distance formula
Types of Quadrilaterals • KITE • 2 pairs of adjacent sides equal in length • Prove using the distance formula
Example: Verify that quadrilateral EFGH, formed by joining the midpoints of ABCD, is a parallelogram.