Query about Question 7 from "PrepSwift Quant Tickbox Quiz #10 (Geometry Column 1)" [6600]

GRE GRE Quant Problem Solving
1

https://prepswift.gregmat.com/quizzes/quiz/prepswift-quant-tickbox-quiz-10-geometry-column-1 (Question 7)

I’m confused about this question. If z+y+ the unknown angle = 180 and x is an obtuse angle, then it seems like the sum of z+y+x has to be greater than 180.

2

This does not need to be true. By the exterior angle theorem, z + y = x, and there’s no information given to you that strictly requires z + y > 90^{\circ}