Sign up for your FREE 7-Day trialGet instant access to all the benefits of SparkNotes PLUS! Cancel within the first 7 days and you won't be charged. We'll even send you a reminder.
SparkNotes Plus subscription is $4.99/month or $24.99/year as selected above. The free trial period is the first 7 days of your subscription. TO CANCEL YOUR SUBSCRIPTION AND AVOID BEING CHARGED, YOU MUST CANCEL BEFORE THE END OF THE FREE TRIAL PERIOD. You may cancel your subscription on your Subscription and Billing page or contact Customer Support at custserv@bn.com. Your subscription will continue automatically once the free trial period is over. Free trial is available to new customers only.
Step 2 of 4
Choose Your Plan
Step 3 of 4
Add Your Payment Details
Step 4 of 4
Payment Summary
Your Free Trial Starts Now!
For the next 7 days, you'll have access to awesome PLUS stuff like AP English test prep, No Fear Shakespeare translations and audio, a note-taking tool, personalized dashboard, & much more!
Thanks for creating a SparkNotes account! Continue to start your free trial.
Please wait while we process your payment
Your PLUS subscription has expired
We’d love to have you back! Renew your subscription to regain access to all of our exclusive, ad-free study tools.
Did you know you can highlight text to take a note?x
Tangent Lines
A tangent line is a line that
intersects a
circle at one point. Such a
line is said
to be tangent to that circle. The point at which the circle and the line
intersect is the point of tangency.
Figure %: A tangent line
In the figure above, the line l is tangent to the circle C. Point T is
the point of tangency.
When a radius of a circle is drawn to a point of tangency (from the center,
of the circle, of course), that radius is
perpendicular to the tangent line
containing
that point of tangency. This means that for any tangent line, there exists a
perpendicular radius.
Figure %: A tangent line is perpendicular to a radius
A tangent segment is a segment
with one
endpoint at the point of tangency and its other endpoint somewhere on the
tangent line. A tangent segment is also perpendicular to the radius of the
circle whose endpoint is the point of tangency.
Figure %: A tangent segment
Secant Lines
A secant line is a line that intersects a circle at two points. Every
secant line, therefore, contains a chord of the circle it intersects.
