To define extremal length, we need to first introduce several related quantities.

Other related quantities, the scalar products of pairs of four-vectors, are also invariant.

The term "gyromagnetic ratio" is sometimes used as a synonym for a different but closely related quantity, the g-factor.

Mass and weight are different, but related quantities.

To get around this, they typically measure a related quantity.

In many cases, instead of measuring target course many systems measured a related quantity called angle on the bow.

However, in a technical sense, spins are not strictly vectors, and they are instead described as a related quantity: a spinor.

During combat, the actual course of the target was not usually determined but instead the skippers determined a related quantity called "angle on the bow."

Below you can find a list with physical sound field quantities and the related psychoacoustical quantities of corresponding auditory events.