Because these triangles are congruent, then angle a is the same degree measure as angle x; angle b is the same as y; and angle c is the same as z. We also know that, because of the Triangle Angle-sum Theorem, all the angles of a triangle have to add up to equal 180 degrees. So for us that means that a+b+c(which is also z) = 180. 50 + 2x + 40 + 4x + 8 = 180. Combining like terms we have 6x + 98 = 180. Subbtracting 98 from both sides gives us 6x = 82 and x = 13 2/3
