Rest length and dilated time in five-dimensional spacetime

It is shown how, based on the special theory of relativity, in a five-dimensional spacetimethrough geometric construction without oblique coordinate systems and scale changes restlengths and dilated times can be determined. The rest system of the relativistically moving bodyis the observer´s system rotated around the time axis into the fifth dimension. Superluminalvelocities can also occur there.Sections:1. Introduction2. Determination of dilated time and rest length3. Justification of the construction method4. Adjustment by the fifth dimension5. Movement in ℝ6. Observer in the reference system S´7. Superluminal velocity at t´< l8. Summary and outlook