RECTANGLES

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RECTANGLES • Recognize and apply properties of rectangles. • Determine whether parallelograms are rectangles. Parts of the tennis court are marked by parallel and perpendicu lar lines.

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RECTANGLES. Recognize and apply properties of rectangles. Determine whether parallelograms are rectangles. Parts of the tennis court are marked by parallel and perpendicular lines. PROPERTIES OF RECTANGLES. A rectangle is a quadrilateral with four right angles. - PowerPoint PPT Presentation

Transcript of RECTANGLES

Page 1: RECTANGLES

RECTANGLES• Recognize and apply properties of rectangles.• Determine whether parallelograms are

rectangles.

Parts of the tennis court are marked by parallel and perpendicular lines.

Page 2: RECTANGLES

PROPERTIES OF RECTANGLESA rectangle is a quadrilateral with four right angles.

Since both pairs of opposite angles are congruent, it follows that a rectangle is a special type of parallelogram.

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THEOREMDIAGONALS OF A RECTANGLE

If a parallelogram is a rectangle, then the diagonals are congruent.

A B

CD

BDAC

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Key Concept RectanglesProperties1. Opposite sides are congruent and

parallel

A B

CD

ADBCDCAB

ADBCDCAB||||

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1. Opposite sides are congruent and parallel

2. Opposite angles are congruent

A B

CD

Key Concept RectanglesProperties

DBCA

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1. Opposite sides are congruent and parallel

2. Opposite angles are congruent

3. Consecutive angles are supplementary

A B

CD

Key Concept RectanglesProperties

180180180180

AmDmDmCmCmBmBmAm

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1. Opposite sides are congruent and parallel

2. Opposite angles are congruent

3. Consecutive angles are supplementary

4. Diagonals are congruent and bisect each other.

A B

CD

Key Concept RectanglesProperties

BDAC

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1. Opposite sides are congruent and parallel

2. Opposite angles are congruent

3. Consecutive angles are supplementary

4. Diagonals are congruent and bisect each other.

5. All four angles are right angles.

A B

CD

Key Concept RectanglesProperties

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Example 1 Diagonals of a RectangleP O

NM

MNOP is a rectangleMO is 6x + 14, PN is 9x + 5Find x

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Example 1 Diagonals of a RectangleP O

NM

MNOP is a rectangleMO is 6x + 14, PN is 9x + 5Find x

Solution:

xxxxx

339

531459146 Diagonals of a rectangle are congruent

Subtract 6x from each side

Subtract 5 from each side

Divide each side by 3

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Example 2 Angles of a Rectangle

A D

CB

(4x + 5)°

(9x + 20)°

Find x

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Example 2 Angles of a Rectangle

A D

CBSolution:

565139025139020954

xx

xxx Angle addition theorem

Simplify

Subtract 25 from each side

Divide each side by 13

(4x + 5)°

(9x + 20)°

Find x

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PROVE THAT PARALLELOGRAMS ARE RECTANGLES

THEOREMIf the diagonals of a parallelogram are congruent, then the parallelogram is a rectangle

A B

CD

BDAC

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Example 3 Rectangle on a Coordinate PlaneQuadrilateral F(-4, -1), G(-2, -5), H(4, -2), J(2, 2)Determine whether FGHI is a rectangle.

2

1

-1

-2

-3

-4

-5

-4 -2 2 4

F

G

H

J