Answer: x = 12 degrees.
Explanation:
The triangle ABC is a right triangle, which means that it has a right angle of 90 degrees.
This is represented by the small square on the bottom-left corner of the triangle.
The angle DBC is 78 degrees. There is also the angle of ABD, which is represented by X.
The right angle is equivalent to 78 degrees and x. You can represent this in an equation, where the sum of 78 degrees and x = 90 degrees, the right angle:
78 + x = 90
x = 12