The slope of a position-time (PT) graph represents velocity, calculated as the change in position over the change in time. This relationship is established because the slope formula, ΔY/ΔX, translates to meters per second when Y is position and X is time. Consequently, the slope directly indicates the rate of change of position, which is defined as velocity. Understanding this connection clarifies why the slope of a PT graph equals the corresponding value on a velocity-time (VT) graph. This fundamental concept illustrates the relationship between position, time, and velocity in physics.