Finding the unknown angle in a geometry problem.

The given angle is . The vertical line and the horizontal line form a right angle, which is . The angle between the vertical line and the slanted line is the unknown angle.

The sum of the angles formed by the intersection of the slanted line and the horizontal line is .
The angle adjacent to the angle is .

The sum of the angles formed by the intersection of the slanted line and the vertical line is also .
The angle adjacent to the right angle ( ) and the unknown angle is .
The sum of the unknown angle and the angle is .
Therefore, the unknown angle is .

Final Answer: The final answer is