The instantaneous speed is always equal to the magnitude of instantaneous velocity. Why?

Instantaneous speed $\mathrm{V}={\mathrm{Lim}}_{\mathrm{\Delta t}\to 0}\frac{\mathrm{\Delta x}}{\mathrm{\Delta t}}$
Instantaneous velocity $\overrightarrow{\mathrm{V}}={\mathrm{Lim}}_{\mathrm{\Delta t}\to 0}\frac{\overrightarrow{\mathrm{\Delta x}}}{\mathrm{\Delta t}}$
Small interval of time $∆\mathrm{t}$ , the magnitude of displacement $|∆\overrightarrow{\mathrm{X}}|$ is equal to the length of the path $∆$X.
So instantaneous speed is always equal to the magnitude of instantaneous velocity.