Exploring Tangent Lines to Circles
Part 1: Tangents and Angles
In the graph, the line shown is tangent to the circle at point C.
Move point D around and note how the angle between the tangent line and segment CD changes.
Make the angle a RIGHT angle!
Move point D until the angle is a right angle. (Be sure to click and drag point D). What is true about segment CD when the angle measure is 90 degrees?
Part 2: What is true about two intersecting tangents to a circle?
In the graph shown, the circle has two tangent lines that intersect. Look closely at the pink line segments (CG and FG) .
Answer the question below BEFORE clicking to show the lengths of the segments.
What appears to be true about the lengths of segments CG and FG? Once you answer, click to show the lengths. Also, try moving points C and F around.