The comparison triangle shows why faster motion raises gamma: changing speed from 3 to 4 makes the remaining quiet leg shrink from 4 to 3. The exact contrast is a clean toy model, while real speed comparisons depend on how the motion and reference frame are measured.
A second right triangle changes one speed and shows gamma increasing. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
A faster speed leaves a shorter quiet leg
Changing speed from 3 m/s to 4 m/s changes the quiet leg from 4 m/s to 3 m/s.