6-4 Properties of Rhombuses, Rectangles, and Squares

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6-4 Properties of Rhombuses, Rectangles, and
Squares
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Special Parallelograms

• A rhombus is a parallelogram with four congruent
  sides.
• A rectangle is a parallelogram with
  four right angles.
• A square is a parallelogram with four congruent
  sides and four right angles.

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Classifying Special Parallelograms

• Is parallelogram ABCD a
  rhombus, a rectangle, or a
  square? Explain.
• ?Is parallelogram EFGH a
  rhombus, a rectangle, or a
  square? Explain.

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Rhombus Properties

• Theorem 6-13 If a parallelogram is a rhombus,
  then its diagonals are perpendicular.
• Theorem 6-14 If a parallelogram is a rhombus,
  then each diagonal bisects a pair of opposite
  angles.

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Finding Angle Measures

• What are the measures of the numbered angles in
  rhombus ABCD?

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? What are the measures of the numbered angles in
rhombus PQRS?
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Rectangle Properties

• Theorem 6-15 If a parallelogram is a rectangle,
  then its diagonals are congruent.

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Finding Diagonal Length

• If SF 2x 15 and RB 5x 12, what is the
  length of a diagonal of rectangle RSFB?

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? If LN 4x 17 and MO 2x 13, what are the
lengths of the diagonals of rectangle LMNO?