Discover the relationship between the angle created by two tangents and the intercepted arcs.
Then use the app to practice finding different unknowns.

1. Check all three boxes and move point C and A around to change the measurements.
2. Make a conjecture about the relationship between the measure of angle DCE, measure of arc DE, and measure of arc DFE.
3. Test your conjecture by changing the measurements.
4. Practice finding different unknowns.
a) Calculate the measure of angle DCE given the two intercepted arc measurements. [Uncheck the first box, move point C or A, then calculate. Check the first box to check your answer. Repeat.]
b) Calculate the measure of angle DCE given only one of the intercepted arc measurements. [Leave only the second or third box checked, move point A or C, then calculate. Check the first box to check your answer. Repeat.]