For a circular arc, chord length is calculated with c = 2r sin(θ/2), where r is the radius and θ is the subtended central angle. The half-angle inside the sine function connects the angular geometry to the straight-line span. This relationship lets engineers determine a required dimension from known circular geometry.
As θ increases while the radius remains fixed, the chord grows and eventually approaches the circle’s diameter. This behavior shows how the separation between arc endpoints depends on the subtended angle. Engineers can use the radius-angle relationship to anticipate endpoint positions and maintain dimensional control in curved layouts.
Chord length and the curved arc describe different geometric distances between the same endpoints. The chord supplies the direct straight-line reference, while the arc follows the curve connecting those points. Keeping these measures distinct helps engineers select the appropriate dimension when developing geometric models, checking layouts, or specifying a linear span.
First identify the two endpoints of the circular feature and establish the radius and subtended central angle when they are known. Substitute those values into c = 2r sin(θ/2) to obtain the straight-line dimension. In computer-aided design, engineers can then compare the calculated value with the modeled geometry to support dimensional control.
In geometric modeling and computer-aided design, chord length provides a direct dimension between selected points on curved geometry. Engineers can use it to specify, inspect, and control the placement of features in a layout. Accurate chord measurements help maintain intended dimensions during design development and provide a consistent basis for checking modeled geometry.
For an airfoil section, chord length defines the reference distance from the leading edge to the trailing edge. Engineers use this distance when specifying the section and evaluating its geometry in relation to performance. Accurate chord measurement establishes a consistent dimensional reference, helping connect the airfoil’s geometric description with engineering analysis.