Three Relationships, and the Angle Actually Asked

Angles come in three relationships — supplementary to 180°, complementary to 90°, and vertical and equal — triangles carry a 180° sum, and similar triangles scale by matched sides. Watch where the points leak: confusing the relationships, flipping a similarity ratio, and reporting the solved variable instead of the angle that was actually asked.

8 STEPS · 6 QUICK CHECKS · 180, 90, or equal · answer the angle, not x · v1