Make a conjecture about the angle created by two tangent lines in relation to the intercepted arcs.

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