Announcements

• Tomorrow we will all get on the same page– 359 2-20 even (you might have to do 1-9

odds)– 2 page packet from Friday– Tonight's homework

9-7 Circles

• Theorem • If two chords intersect in a circle, then the

product of the lengths of the segments of one chord equals the products of the segments of the other chord.

A

BD

CEA ∙ EB = EC ∙ ED

E

Solve for x

0%

5%

0%

95%

0%

A

BD

CE

9

6

3

x

1. 1

2. 2

3. 3

4. 4

5. 5

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26

A

B

D

C

E

• Theorem– Two secants from the same point: Take one and

multiply the outside part times the whole thing and that’s equal to the same thing of the other.

EA ∙ EB = EC ∙ ED

Solve for x

0%

0%

0%

0%

100%

0%

0%

0%

A

B

D

C

E6

x

75

1. 12. 23. 34. 45. 56. 67. 78. 8

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26

A

D

C

E

• Theorem – A tangent and a secant from the same point: Take

the secant and multiply the outside part times the whole thing and that’s equal to the square of the tangent.

(EA)2 = EC ∙ ED

Solve for x

0%

89%

5%

5%

0%

0%

0%

0%

0%

AB

D

CE

x

124

1. 12. 23. 34. 45. 56. 67. 78. 89. 9

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26

SPICSAPage 364

2-12 even and 22