# Lines Tangent and Secant to a Circle的副本

- Author:
- xiaodandan, Anna

The length of segment a is the distance from the center of the circle to line d.
You can change the length of segment a by adjusting the slider. Use the slider and the applet to answer the questions below.

Using the slider, find the values where the line intersects the circle at
a) 0 points
b) 1 point
c) 2 points
What do you notice about the relationship between the distance the line is from the center and the number of time the line intersects the circle?
For line d to be tangent to circle E, what must be true?