To solve this problem, we need to use the fact that the sum of angles in a quadrilateral is $360^\circ$. This shape is a trapezoid with three known angles.

Given information:

1. There's a right angle of $90^\circ$ in the lower left corner.
2. One angle is labeled $x^\circ$.
3. Another angle is labeled $(x - 40)^\circ$.

Steps to Solve:

1. Let’s label the angles as follows:

   • Angle 1 = $90^\circ$
   • Angle 2 = $x^\circ$
   • Angle 3 = $(x - 40)^\circ$
   • Angle 4 = the unknown angle.

2. Since it is a quadrilateral, we know that: $90 + x + (x - 40) + \text{Angle 4} = 360$

3. Simplify and solve for $x$:

   • Rearranging for Angle 4, we assume it's $90^\circ$