Final answer:
The two angles (angle BAC and angle CAD) are collinear and add up to 0 degrees.
Step-by-step explanation:
In triangle ABC, we have angle BAC = 129 degrees and angle CAD = 51 degrees. To find the measure of angle BAD, we subtract the sum of angle BAC and angle CAD from 180 degrees. So, angle BAD = 180 degrees - (129 degrees + 51 degrees) = 180 degrees - 180 degrees = 0 degrees.
Since angle BAD is 0 degrees, the two angles (angle BAC and angle CAD) are collinear, meaning they lie on the same line.
The two angles are collinear and add up to 0 degrees.