sharpen solution If our bullet bounced as the lab technician desribed, what do we know should be true about mystery angles x and y? x and y are supplementary x is less than y x is equal to y nothing--they could be any angles yº TIRE TRACKS xº Tick marks indicate equal angles Tick marks on angles are used to show that the angles are equal, even if we don't know what size the angles are. Each set of equal angles has a different number of ticks, so you can mark more than one set on the same sketch if you need to. Things that bounce equally bounce like this. bounce Remember--your sketch isn't usually accurate enough to see by eye whether two angles are equal. Unless you're told otherwise, a sketch is just a sketch. Even if the angles drawn look pretty close to the real angles, you can't rely on your eye or a protractor--you've gotta work the angles out. These tick marks on the angles show that they are equal. 30 Chapter 1