What if the parallelogram is not a regular square and the angles are more or less than 90? Must we assume that the shapes are regular on both the old and new GRE? Any input on the discussion would be much appreciated. Thanks

Answers will never be based on assumptions that are not posed in the problem itself. So, let’s see what we can do here.

Each angle measure of the triangle is 180-x, and we know that angles add up to 180. Thus, 3(180-x)=180 which means that 180-x=60. At this point we now know that the triangle is indeed equilateral. So we also find that x=120.

Now consider the quadrilateral. We know that each angle measure is 180-y, and that the angles add up to 360. Thus, 4(180-y)=360, so 180-y=90 meaning that each angle is 90 degrees. Now we have all the information we need to answer the problem.

Also, the concept tells us that the sum of all the exterior angles, angles like the ones that are presented here, add up to 360 no matter the shape. This would help us to find the values of x,y in an easier manner!