This is calculator work. Type in 0.8 inverse tangent and find 38.6598, which, rounded, matches answer D.
One way to determine the scale factor of a dilation is if you are using a graph then you can pick two corresponding points of the before and after and divide them and you can get the scale factor.
The second one is true because if you have 2 angle measures then you can automatically find the third because we know that all the angles of a triangle add up to 180 so lets say that one angle is 94 degrees and another is 38 degrees we would add those two up to get 132 and then we would subtract that from 180 to get the third angle which would be 48 degrees.
The third one, vertical angles have a common vertex, but they are never adjacent angles. Also, vertical angles are always congruent.
The answer to your question is 5
