Can you me to find the value of x and z? ?

  Due to how the lines n and m are parallel, you know that all of the triangles in the image are right triangles. Due to this, you can substitute values accordingly into the pythagorean theorem, or a^2+b^2=c^2. Hence, you can find the values of X and Z after substituting your known values for each triangle into this theorem accordingly.

Whose mistake? can you give more details to what the question is asking?

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