Perpendicular Bisector of a Line To find the equation of the perpendicular bisector of a line...

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Perpendicular Bisector of a Line

To find the equation of the perpendicular bisector of a line segment :

1. Find the midpoint

2. Find the slope of the given line segment

3. Find the perpendicular slope ( flip the fraction and change signs )

4. Use the midpoint ( a , b ) and the perpendicular slope in the

point – slope equation.

2

,2

midpoint 2121 yyxx

12

12

xx

yym

baxmy

Perpendicular Bisector of a Line

EXAMPLE : Find the equation of the perpendicular bisector of the line segment with endpoints ( 2 , 7 ) and ( 4 , - 1 ).

Perpendicular Bisector of a Line

EXAMPLE : Find the equation of the perpendicular bisector of the line segment with endpoints ( 2 , 7 ) and ( 4 , - 1 ).

1. 3,32

6,

2

6

2

)1(7,

2

42

2,

2 midpoint 2121

yyxx

Perpendicular Bisector of a Line

EXAMPLE : Find the equation of the perpendicular bisector of the line segment with endpoints ( 2 , 7 ) and ( 4 , - 1 ).

1.

2.

3,32

6,

2

6

2

)1(7,

2

42

2,

2 midpoint 2121

yyxx

1

4

2

8

24

71

12

12

xx

yym

Perpendicular Bisector of a Line

EXAMPLE : Find the equation of the perpendicular bisector of the line segment with endpoints ( 2 , 7 ) and ( 4 , - 1 ).

1.

2.

3.

3,32

6,

2

6

2

)1(7,

2

42

2,

2 midpoint 2121

yyxx

1

4

2

8

24

71

12

12

xx

yym

4

1m

Perpendicular Bisector of a Line

EXAMPLE : Find the equation of the perpendicular bisector of the line segment with endpoints ( 2 , 7 ) and ( 4 , - 1 ).

1.

2.

3.

4.

3,32

6,

2

6

2

)1(7,

2

42

2,

2 midpoint 2121

yyxx

1

4

2

8

24

71

12

12

xx

yym

4

1m

334

1

xy

baxmy Substitute the midpoint and perpendicular slope into point – slope form

Perpendicular Bisector of a Line

EXAMPLE : Find the equation of the perpendicular bisector of the line segment with endpoints ( 0 , 3 ) and ( - 3 , 9 ).

Perpendicular Bisector of a Line

EXAMPLE : Find the equation of the perpendicular bisector of the line segment with endpoints ( 0 , 3 ) and ( - 3 , 9 ).

1.

6,2

3

2

12,

2

3

2

93,

2

)3(0

2,

2 midpoint 2121 yyxx

Perpendicular Bisector of a Line

EXAMPLE : Find the equation of the perpendicular bisector of the line segment with endpoints ( 0 , 3 ) and ( - 3 , 9 ).

1.

2.

6,2

3

2

12,

2

3

2

93,

2

)3(0

2,

2 midpoint 2121 yyxx

1

2

3

6

03

39

12

12

xx

yym

Perpendicular Bisector of a Line

EXAMPLE : Find the equation of the perpendicular bisector of the line segment with endpoints ( 0 , 3 ) and ( - 3 , 9 ).

1.

2.

3.

6,2

3

2

12,

2

3

2

93,

2

)3(0

2,

2 midpoint 2121 yyxx

1

2

3

6

03

39

12

12

xx

yym

2

1m

Perpendicular Bisector of a Line

EXAMPLE : Find the equation of the perpendicular bisector of the line segment with endpoints ( 0 , 3 ) and ( - 3 , 9 ).

1.

2.

3.

4.

6,2

3

2

12,

2

3

2

93,

2

)3(0

2,

2 midpoint 2121 yyxx

1

2

3

6

03

39

12

12

xx

yym

2

1m

62

3

2

1

62

3

2

1

xy

xy

baxmy

Substitute the midpoint and perpendicular slope into point – slope form

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