All sides of a rhombus are equal.
So the triangle containing the marked angle 124 degrees is isosceles and the base angles x and z are equal.
So, because there are 180 degrees in a triangle.
x + z + 124 = 180
z + z + 124 = 180 ( because m < x = m < z)
2z = 180 -124 = 56
z = 56/2 = 28 degrees (answer).
