Exploring the Exterior Angle Theorem
For the first triangle, find the measure of angle ACD with the value of angle ACB.
For the second triangle find the value if angle ACD with the given values.
For the third triangle, move point C along line segment BD and see how the given angles change. Write down any observations you can make. Also look at the angles without measures and how they change.
For the final triangle, find the value of exterior angle ACD and use the angle measure to check your answer.