Estimate the measure of ∠BCD to the nearest 10

120 degrees.

Step-by-step explanation: A 90-degree angle would be a right angle. The segments would be perpendicular. In a 180-degree angle, the line would be flat. This angle is between these two angle measures. It appears quite close to a 120-degree angle such as the one shown below:

Because of this, I would estimate that the angle is around 120 degrees. It may be 130 degrees or 110 degrees but it appears to be approximately 120 degrees.

a

step-by-step explanation:

ca = ec

cpctc makes it so that corresponding parts of the triangle you proved to be equal are equal, the other options aren't part of the part of the triangles you proved to be equal.