What is the distance between the walls?

If you flip the 30-60-90 triangles so they look similar, and find the difference between the length of 60, and the length of 40.

40÷60 =.6666 etc

You can prove this by plugging in
60 •.66666 = 39.9999 or about 40.

The triangle I started with had a length of 60, so just used the tangent of 60° to find the adjacent.
Since we know the relationship of the triangles,
Multiply your answer, 103.923 •.666666
Which equals 69.2819
69.2819 is the length of the 40 triangle.

Add them together, and you get 173.2049.

Or 173.20 m