Observe all the triangles and compare the brake lights with the slot by dragging it over the slot. What can be inferred about measure angle X, Y, and Z? What can be inferred about their adjacent sides? Using this reasoning, which brake lights are similar to the slot?
Measure angles X, Y, and Z are congruent to at most one angle in the slot. This tells us that their adjacent sides would lie on the same line segment with the slot. Because of this, we can also say that the adjacent sides are proportional to the slot's sides. Hence, all brake lights are similar to the slot.