Mathematical, literal or symbolic expression that describes a fundamental relationship between magnitudes of a geometric figure.
Example
The Pythagorean theorem is a metric relationship in a right triangle.
Educational note
In secondary education math programs, the focus is mainly on metric relationships in circles and metric relationships in right triangles or other triangles.
All formulas used to calculate the area of plane figures and the volume of three-dimensional figures are also metric relationships, in that they establish relationships between magnitudes of these figures.