This is a rhombus becuase it a quadralterial and it has four right triangles, and it diagonals bisect each others so it cant be a trapezoid, and paralleolgram. and it doesnt have four right corner angles so it cant be a square or rectangle or kite.
A rhombus inner angle measure is 90 degrees.
So
This means the upper left angle of the top triangle measure is 58 becuase triangle interior theorem.
Since a rhombus bisects angles, angle x measure 58.