Angles Formed by Intersecting Tangents and Secants.
READ the instructions on the right and INTERACT with the GeoGebra applet below.
|
|
|
|
Investigation Steps
Click on the 
icon to reset the diagram.
Figure 1
- Move point C on the circle to change the direction of line CD and the position of the intersection point D. What happens to the blue arc as the red arc gets larger?
- What is the consistent sum of the blue and red arc at any position of point C?
- What is the difference of the arcs as the red arc decreases? How does this affect the measure of the blue angle at Point D?
- What happens if the lines don´t intersect?
Figure 2
- Move point E on the circle to change the direction of secant ED. How does that affect the red arc CE?
- Move points D or B. Which arc changes? How does this affect the measure of the angle?
- What do you think the relationship would be for an intersecting secant and tangent?
|