Please answer correctly

The line that splits the x is parallel to the other two horizontal lines. On account of this, you can get that that the topmost part of it's angle is 30° because it is the congruent alternate interior angle to the topmost 30°. The same applies with the bottomost part of the x's angle and the 40° on the bottomost line. Then you get that part of x is 30° and the other part is 40°, so x as a whole is 70°, I think.

i think it would be 42cm