CK-12 Geometry Concepts

9.11. Segments from Secants and Tangents http://www.ck12.org

x^2 = 4 ( 4 + 12 )

x^2 = 4 · 16 = 64

x= 8

Example B

Find the value of the missing segment.

Use the Tangent Secant Segment Theorem. Square the tangent and set it equal to the outer part times the whole
secant.

202 =y(y+ 30 )

400 =y^2 + 30 y

0 =y^2 + 30 y− 400

0 = (y+ 40 )(y− 10 )

y=− 40 HHH , 10

Example C

Fill in the blank and then solve for the missing segment.

= ( 4 + 5 )

x^2 = 4 ( 4 + 5 )

x^2 = 36

x= 6

Watch this video for help with the Examples above.

MEDIA

Click image to the left for more content.

CK-12 Foundation: Chapter9SegmentsfromSecantsandTangentsB

Vocabulary

Acircleis the set of all points that are the same distance away from a specific point, called thecenter. Aradiusis
the distance from the center to the circle. Achordis a line segment whose endpoints are on a circle. Adiameteris
a chord that passes through the center of the circle. The length of a diameter is two times the length of a radius. A
central angleis the angle formed by two radii and whose vertex is at the center of the circle. Aninscribed angle
is an angle with its vertex on the circle and whose sides are chords. Theintercepted arcis the arc that is inside