Question 845210
To begin you should know that the sum of all the angles in a quadrilateral = 360 degrees.

Now that we know that the sum is 360 and we know the other three angles, it will be easy to solve for x.

90 + 50 + 48 + x = 360.

188 + x = 360.

Subtract 188 from both sides to simplify and isolate x.

x = 172. Therefore x is 172 degrees. 

Now let's check to see if this is correct

90 + 50 + 48 + 172 = 360 

360 = 360. It checks out. The problem is solved.